Test file fixes for bugs 20129, 31931 and 34225


mysql-test/suite/parts/r/partition_basic_symlink_innodb.result:
  Manual merge, new test case to be modified for Bug#20129
mysql-test/suite/parts/r/partition_basic_symlink_myisam.result:
  Manual merge, new test case to be modified for Bug#20129
mysql-test/suite/parts/r/partition_engine_innodb.result:
  Manual merge, fix for bug#31931
mysql-test/suite/parts/r/partition_engine_myisam.result:
  Manual merge, fix for bug#31931
mysql-test/suite/parts/t/disabled.def:
  These should work now since Bug#34225 is fixed
sql/ha_partition.cc:
  Bug#20129: partition maintenance command not working with crashed tables
  
  Fix for compiler warnings.