Post-push fix.
Problem: In a previous patch for BUG#39934, rpl_idempotency.test
was split in two tests. The mtr suppressions in the original test
did not make it into the new test. This caused pushbuild warnings.
Fix: copy the mtr suppressions from rpl_idempotency.test to
rpl_row_idempotency.test

General overview:
The logic for switching to row format when binlog_format=MIXED had
numerous flaws. The underlying problem was the lack of a consistent
architecture.
General purpose of this changeset:
This changeset introduces an architecture for switching to row format
when binlog_format=MIXED. It enforces the architecture where it has
to. It leaves some bugs to be fixed later. It adds extensive tests to
verify that unsafe statements work as expected and that appropriate
errors are produced by problems with the selection of binlog format.
It was not practical to split this into smaller pieces of work.

Problem 1:
To determine the logging mode, the code has to take several parameters
into account (namely: (1) the value of binlog_format; (2) the
capabilities of the engines; (3) the type of the current statement:
normal, unsafe, or row injection). These parameters may conflict in
several ways, namely:
 - binlog_format=STATEMENT for a row injection
 - binlog_format=STATEMENT for an unsafe statement
 - binlog_format=STATEMENT for an engine only supporting row logging
 - binlog_format=ROW for an engine only supporting statement logging
 - statement is unsafe and engine does not support row logging
 - row injection in a table that does not support statement logging
 - statement modifies one table that does not support row logging and
   one that does not support statement logging
Several of these conflicts were not detected, or were detected with
an inappropriate error message. The problem of BUG#39934 was that no
appropriate error message was written for the case when an engine
only supporting row logging executed a row injection with
binlog_format=ROW. However, all above cases must be handled.
Fix 1:
Introduce new error codes (sql/share/errmsg.txt). Ensure that all
conditions are detected and handled in decide_logging_format()

Problem 2:
The binlog format shall be determined once per statement, in
decide_logging_format(). It shall not be changed before or after that.
Before decide_logging_format() is called, all information necessary to
determine the logging format must be available. This principle ensures
that all unsafe statements are handled in a consistent way.
However, this principle is not followed:
thd->set_current_stmt_binlog_row_based_if_mixed() is called in several
places, including from code executing UPDATE..LIMIT,
INSERT..SELECT..LIMIT, DELETE..LIMIT, INSERT DELAYED, and
SET @@binlog_format. After Problem 1 was fixed, that caused
inconsistencies where these unsafe statements would not print the
appropriate warnings or errors for some of the conflicts.
Fix 2:
Remove calls to THD::set_current_stmt_binlog_row_based_if_mixed() from
code executed after decide_logging_format(). Compensate by calling the
set_current_stmt_unsafe() at parse time. This way, all unsafe statements
are detected by decide_logging_format().

Problem 3:
INSERT DELAYED is not unsafe: it is logged in statement format even if
binlog_format=MIXED, and no warning is printed even if
binlog_format=STATEMENT. This is BUG#45825.
Fix 3:
Made INSERT DELAYED set itself to unsafe at parse time. This allows
decide_logging_format() to detect that a warning should be printed or
the binlog_format changed.

Problem 4:
LIMIT clause were not marked as unsafe when executed inside stored
functions/triggers/views/prepared statements. This is
BUG#45785.
Fix 4:
Make statements containing the LIMIT clause marked as unsafe at
parse time, instead of at execution time. This allows propagating
unsafe-ness to the view.

                              
RBR was not considering the option --slave-skip-errors.
                              
To fix the problem, we are reporting the ignored ERROR(s) as warnings thus avoiding 
stopping the SQL Thread. Besides, it fixes the output of "SHOW VARIABLES LIKE 
'slave_skip_errors'" which was showing nothing when the value "all" was assigned 
to --slave-skip-errors.
                  
@sql/log_event.cc
  skipped rbr errors when the option skip-slave-errors is set.
@sql/slave.cc
  fixed the output of for SHOW VARIABLES LIKE 'slave_skip_errors'"
@test-cases
  fixed the output of rpl.rpl_idempotency
  updated the test case rpl_skip_error

Problem: Many test cases don't clean up after themselves (fail
to drop tables or fail to reset variables). This implies that:
(1) check-testcase in the new mtr that currently lives in
5.1-rpl failed. (2) it may cause unexpected results in
subsequent tests.
Fix: make all tests clean up.
Also: cleaned away unnecessary output in rpl_packet.result
Also: fixed bug where rpl_log called RESET MASTER with a running
slave. This is not supposed to work.
Also: removed unnecessary code from rpl_stm_EE_err2 and made it
verify that an error occurred.
Also: removed unnecessary code from rpl_ndb_ctype_ucs2_def.

Problem: during a refactoring of mtr, a pattern for suppressing a warning from lowercase_table3 was lost.
Fix: re-introduce the suppression.
Problem 2: suppression was misspelt as supression. Fixed by adding a p.

Problem 1: tests often fail in pushbuild with a timeout when waiting
for the slave to start/stop/receive error.
Fix 1: Updated the wait_for_slave_* macros in the following way:
- The timeout is increased by a factor ten
- Refactored the macros so that wait_for_slave_param does the work for
the other macros.
Problem 2: Tests are often incorrectly written, lacking a
source include/wait_for_slave_to_[start|stop].inc.
Fix 2: Improved the chance to get it right by adding
include/start_slave.inc and include/stop_slave.inc, and updated tests
to use these.
Problem 3: The the built-in test language command
wait_for_slave_to_stop is a misnomer (does not wait for the slave io
thread) and does not give as much debug info in case of failure as
the otherwise equivalent macro
source include/wait_for_slave_sql_to_stop.inc
Fix 3: Replaced all calls to the built-in command by a call to the
macro.
Problem 4: Some, but not all, of the wait_for_slave_* macros had an
implicit connection slave. This made some tests confusing to read,
and made it more difficult to use the macro in circular replication
scenarios, where the connection named master needs to wait.
Fix 4: Removed the implicit connection slave from all
wait_for_slave_* macros, and updated tests to use an explicit
connection slave where necessary.
Problem 5: The macros wait_slave_status.inc and wait_show_pattern.inc
were unused. Moreover, using them is difficult and error-prone.
Fix 5: remove these macros.
Problem 6: log_bin_trust_function_creators_basic failed when running
tests because it assumed @@global.log_bin_trust_function_creators=1,
and some tests modified this variable without resetting it to its
original value.
Fix 6: All tests that use this variable have been updated so that
they reset the value at end of test.

    without PK
Bug#31609 Not all RBR slave errors reported as errors
bug#32468 delete rows event on a table with foreign key constraint fails

The first two bugs comprise idempotency issues.
First, there was no error code reported under conditions of the bug
description although the slave sql thread halted.
Second, executions were different with and without presence of prim key in
the table.
Third, there was no way to instruct the slave whether to ignore an error
and skip to the following event or to halt.
Fourth, there are handler errors which might happen due to idempotent
applying of binlog but those were not listed among the "idempotent" error
list.

All the named issues are addressed.
Wrt to the 3rd, there is the new global system variable, changeble at run
time, which controls the slave sql thread behaviour.
The new variable allows further extensions to mimic the sql_mode
session/global variable.
To address the 4th, the new bug#32468 had to be fixed as it was staying
in the way.

The rpl_trigger test case indicated a problem with idempotency support when run
under row-based replication, which this patch fixes.

However, despite this, the test is not designed for execution under row-based
replication and hence rpl_trigger.test is not executed under row-based
replication.

The problem is that the test expects triggers to be executed when the slave
updates rows on the slave, and this is (deliberately) not done with row-based
replication.