if binlog_format=mixed

Addition to fix for BUG#34768: fixed test case failures discovered
by pushbuild.


mysql-test/suite/binlog/r/binlog_stm_ps.result:
  Fixed binlog_stm_ps failure when binlog format is statement:
  - this test case makes sence only if binlog format is statement,
    thus execute it only in this mode;
  - added a warning that insert ... select ... limit is not safe
    to execute in statement mode.
mysql-test/suite/binlog/t/binlog_stm_ps.test:
  Fixed binlog_stm_ps failure when binlog format is statement:
  - this test case makes sence only if binlog format is statement,
    thus execute it only in this mode;
  - added a warning that insert ... select ... limit is not safe
    to execute in statement mode.
mysql-test/suite/rpl/t/rpl_optimize.test:
  rpl_optimize test may be executed in various binlog format modes.
  In statement mode delete ... limit issues a warning, in mixed and
  row modes it does not.
  
  Fixed a test case so it is still possible to execute it in all binlog
  format modes by ignoring delete ... limit warnings.
mysql-test/suite/rpl/t/rpl_user_variables.test:
  rpl_user_variables test may be executed in various binlog format modes.
  In statement mode insert ... select ... limit issues a warning,
  in mixed and row modes it does not.
  
  Fixed a test case so it is still possible to execute it in all binlog
  format modes by ignoring insert ... select ... limit warnings.