The --enable_prepare_warnings allows to not discard warnings from autorepair
of crashed table in --ps-protocol mode.

Use this to properly fix the parts.partition_recover_myisam and
maria.maria-recover tests.

Add a test case for the new feature. This also adds missing test coverage
for the case where the same warning is thrown in both prepare and execute
phase.


client/mysqltest.cc:
  Implement new commands --enable-prepare_warnings and --disable_prepare_warnings.
mysql-test/r/mysqltest_ps.result:
  Add test case for new --enable_prepare_warning mysqltest command.
mysql-test/suite/maria/t/maria-recover.test:
  Better fix of test case using new --enable_prepare_warnings command.
mysql-test/suite/parts/t/partition_recover_myisam.test:
  Fix test failure in --ps-protocol mode.
mysql-test/t/mysqltest_ps.test:
  Add test case for new --enable_prepare_warning mysqltest command.

Bug#35161
Fixed memory leak when failing to open a partition.

Bug#20129
Added tests for verifying REPAIR PARTITION.

mysql-test/std_data/parts/t1_will_crash#P#p1_first_1024.MYD:
  Bug#20129: ALTER TABLE ... REPAIR PARTITION ... not working
  
  (see mysql-test/suite/parts/t/partition_repair_myisam.test
  Created by:
  CREATE TABLE t1_will_crash (
    a VARCHAR(255),
    b INT,
    c LONGTEXT,
    PRIMARY KEY (a, b))ENGINE=MyISAM
  PARTITION BY HASH (b)
  PARTITIONS 7;
  INSERT INTO t1_will_crash VALUES ...
  and then
  head -c 1024 var/master-data/test/t1_will_crash#P#p1.MYD
  into this file.
mysql-test/std_data/parts/t1_will_crash#P#p2.MYD:
  Bug#20129: ALTER TABLE ... REPAIR PARTITION ... not working
  
  (see mysql-test/suite/parts/t/partition_repair_myisam.test)
  copy of file right after _mi_mark_file_changed in mi_write
  was done.
mysql-test/std_data/parts/t1_will_crash#P#p2.MYI:
  Bug#20129: ALTER TABLE ... REPAIR PARTITION ... not working
  
  (see mysql-test/suite/parts/t/partition_repair_myisam.test)
  copy of file right after _mi_mark_file_changed in mi_write
  was done.
mysql-test/std_data/parts/t1_will_crash#P#p3.MYI:
  Bug#20129: ALTER TABLE ... REPAIR PARTITION ... not working
  
  (see mysql-test/suite/parts/t/partition_repair_myisam.test)
  copy of file right after *share->write_record was done.
mysql-test/std_data/parts/t1_will_crash#P#p4.MYI:
  Bug#20129: ALTER TABLE ... REPAIR PARTITION ... not working
  
  (see mysql-test/suite/parts/t/partition_repair_myisam.test)
  copy of file right after flush_cached_blocks
mysql-test/std_data/parts/t1_will_crash#P#p6.MYD:
  Bug#20129: ALTER TABLE ... REPAIR PARTITION ... not working
  
  (see mysql-test/suite/parts/t/partition_repair_myisam.test)
  copy of file right after _mi_write_part_record in
  write_dynamic_record returned for the first time.
mysql-test/std_data/parts/t1_will_crash#P#p6_2.MYD:
  Bug#20129: ALTER TABLE ... REPAIR PARTITION ... not working
  
  (see mysql-test/suite/parts/t/partition_repair_myisam.test)
  copy of file right after _mi_write_part_record in
  write_dynamic_record returned for the second time.
mysql-test/std_data/parts/t1_will_crash#P#p6_3.MYD:
  Bug#20129: ALTER TABLE ... REPAIR PARTITION ... not working
  
  (see mysql-test/suite/parts/t/partition_repair_myisam.test)
  copy of file right after _mi_write_part_record in
  write_dynamic_record returned for the third time.
  (data file fully updated).
mysql-test/suite/parts/r/partition_recover_myisam.result:
  Bug#35161
  
  Renamed since it was a test of recover
  and to make repair free for use without
  --myisam-recover
mysql-test/suite/parts/r/partition_repair_myisam.result:
  Bug#20129: ALTER TABLE ... REPAIR PARTITION ... not working
  
  New result file for testing CHECK/REPAIR of partitioned tables
mysql-test/suite/parts/t/partition_recover_myisam-master.opt:
  Bug#35161
  
  Renamed since it was a test of recover
  and to make repair free for use without
  --myisam-recover
mysql-test/suite/parts/t/partition_recover_myisam.test:
  Bug#35161
  
  Renamed since it was a test of recover
  and to make repair free for use without
  --myisam-recover
mysql-test/suite/parts/t/partition_repair_myisam.test:
  Bug#20129: ALTER TABLE ... REPAIR PARTITION ... not working
  
  New test file for testing CHECK/REPAIR of partitioned tables
sql/ha_partition.cc:
  Bug#35161
  
  Fix of memory leak when open of partition failed.

Problem was that auto_repair, is_crashed and check_and_repair was not
implemented in ha_partition.

Solution, implemented them as loop over all partitions for is_crashed and
check_and_repair, and using the first partition for auto_repair.

(Recommit after fixing review comments)

mysql-test/lib/mtr_report.pl:
  Bug#35161: --myisam-recover does not work for partitioned MyISAM tables
  
  Added filter for crashed tables, when testing auto repair
mysql-test/std_data/corrupt_t1#P#p1.MYI:
  Bug#35161: --myisam-recover does not work for partitioned MyISAM tables
  
  Corrupt MYI file for testing auto repair
mysql-test/std_data/corrupt_t1.MYI:
  Bug#35161: --myisam-recover does not work for partitioned MyISAM tables
  
  Corrupt MYI file for testing auto repair
mysql-test/suite/parts/r/partition_repair_myisam.result:
  Bug#35161: --myisam-recover does not work for partitioned MyISAM tables
  
  Result file for testing auto repair of crashed myisam partitions
mysql-test/suite/parts/t/partition_repair_myisam-master.opt:
  Bug#35161: --myisam-recover does not work for partitioned MyISAM tables
  
  opt file for testing auto repair of crashed myisam partitions
mysql-test/suite/parts/t/partition_repair_myisam.test:
  Bug#35161: --myisam-recover does not work for partitioned MyISAM tables
  
  Test file for testing auto repair of crashed myisam partitions
sql/ha_partition.cc:
  Bug#35161: --myisam-recover does not work for partitioned MyISAM tables
  
  Added auto_repair as returning the first partitions auto_repair
  Added is_crashed and check_and_repair as loop over all partitions
sql/ha_partition.h:
  Bug#35161: --myisam-recover does not work for partitioned MyISAM tables
  
  Activating check_and_repair, auto_repair and is_crashed