when a range condition use an invalid DATETIME constant.
Now we do not use invalid DATETIME constants to form end keys for
range intervals: range analysis just ignores predicates with such
constants.  


mysql-test/r/query_cache.result:
  Adjusted result warnings when adding a fix for bug #16249.
mysql-test/r/range.result:
  Added a test case for bug #16249.
mysql-test/t/range.test:
  Added a test case for bug #16249.