datetime of when the current statement began. This also makes SYSDATE()
not safe in replication. (Bug #12562)


mysql-test/r/func_time.result:
  Add new results
mysql-test/t/func_time.test:
  Add tests for new SYSDATE() behavior
sql/item_timefunc.cc:
  Add Item_func_sysdate_local implementation
sql/item_timefunc.h:
  Add Item_func_sysdate_local, so SYSDATE() can behave differently
  than NOW().
sql/lex.h:
  SYSDATE() is no longer an alias for NOW().
sql/sql_yacc.yy:
  Handle SYSDATE()