Fixed a few bugs in hex string generation, in call to val_str for partition expressions, also made code reusable for DEFAULT handling to fix BUG#48464 by introducing function get_cs_converted_string_value, added partition_utf8 test case for UTF8 outputs

Fixed such that we fail if using integer constants for character set fields, now need to have correct constant types

Fixed so that character set constants are encoded as hex strings in frm file, but as utf8 strings in the same manner as default values in show create table and information schema tables

Backport for 5.5

In non debug builds, the statements:
- SHOW PROCEDURE CODE
- SHOW FUNCTION CODE
used to fail with a "syntax error", which is misleading.

These statements have been changed to return the following error for non
debug builds:
ERROR HY000: The 'SHOW PROCEDURE|FUNCTION CODE' feature is disabled; you
need MySQL built with '--with-debug' to have it working

For debug builds (./configure --with-debug), nothing is changed.

Backport for 5.5

Backport to 5.5

BUG#48397, set key_part->length to key_part->store_length isn't correct, store_length is a bit longer

per-file comments:
  mysql-test/r/mysql_upgrade.result
     result updated
  mysql-test/t/mysql_upgrade.test
     --skip-verbose option added to the call

Fixed code review change to ensure that VALUES constants are of the same result type as the field they are constants for

Item_sum::set_aggregator() may be called multiple times during query preparation.
On subsequent calls: verify that the aggregator type is the same,
and re-use the existing Aggregator.


sql/item_sum.cc:
  In Item_sum::set_aggregator(): re-use existing Aggregator if already set.
  
  Remove some friend declarations, add some accessor functions.
  Cleanup some DBUG_ENTER and DBUG_RETURN code.
sql/item_sum.h:
  Make some member fields private, add accessors instead.
  Remove some un-necessary friend declarations.
  Remove some default arguments from constructors.
sql/opt_sum.cc:
  Use accessor functions in Item_sum.
sql/sql_select.cc:
  Fix mis-spelled DBUG_ENTER text.
  Use accessor functions in Item_sum.
sql/sql_yacc.yy:
  Use explicit true/false rather than default arguments when constructing
  Item_sum_xxx objects.

   (backport)
   mysql_upgrade script accepts --upgrade-system-tables option,
   fixing only system tables in this case.

per-file comments:
  client/mysql_upgrade.c
WL#4991 mysql_upgrade --fix-privilege-tables
    --upgrade-system-tables option added.
   if it is set, the tool won't look for the mysqlcheck then
   run_mysqlcheck_fixnames() and run_mysqlcheck_upgrade won't be called.
  mysql-test/r/mysql_upgrade.result
WL#4991 mysql_upgrade --fix-privilege-tables
    test result added
  mysql-test/t/mysql_upgrade.test
WL#4991 mysql_upgrade --fix-privilege-tables
    test case added

BUG#48165, needed to introduce length restrictions on partitioning fields to ensure that no stack overruns occur

Fixed sql_mode issue in BUG#48164, will ignore sql_mode when generating constants, also warnings will not be tolerated

Disabled execution of this test for embedded server until fix for
bug 41971 'Thread state on embedded server is always "Writing to net"'
is back-ported to this tree.

Fixing locale name: en_US.UTF-8 -> en_US.utf8