When constructing a key image stricter date checking (from sql_mode)
should not be enabled, because it will reject invalid dates that the
server would otherwise accept for searching when there's no index.
 
Fixed by disabling strict date checking when constructing a key image.


mysql-test/r/type_date.result:
  Bug #31928: test case
mysql-test/t/type_date.test:
  Bug #31928: test case
sql/sql_select.h:
  Bug #31928: Disable strict date checking when consructing
  a key image