Bug#10568 - Function 'LAST_DAY(date)' does not return NULL for invalid argument.
Manual merge.


include/my_global.h:
  Auto merged
mysql-test/t/heap_hash.test:
  Auto merged
sql/ha_heap.h:
  Auto merged
sql/item_timefunc.cc:
  Auto merged
mysql-test/r/func_time.result:
  Manual merge.
  Used local for the backported fix for Bug#10568.
mysql-test/r/heap_hash.result:
  Bug#10178 - failure to find a row in heap table by concurrent UPDATEs
  Manual merge.
mysql-test/t/func_time.test:
  Manual merge.
  Used local for the backported fix for Bug#10568.
sql/ha_heap.cc:
  Bug#10178 - failure to find a row in heap table by concurrent UPDATEs
  Manual merge.