mysql-test/r/ps_2myisam.result:
  changes in results of select without order by
mysql-test/r/ps_3innodb.result:
  changes in results of select without order by
mysql-test/r/ps_5merge.result:
  changes in results of select without order by
mysql-test/r/ps_6bdb.result:
  changes in results of select without order by
sql/item_cmpfunc.cc:
  do not assign values of left expression of IN/ANN/ANY subquery in case of PS preparation