Consider double values as legal date{time} function's arguments
(i.e. allow dates in internal format YYYYMMDDHHMMSS.XXXXXX).


mysql-test/r/func_sapdb.result:
  Fix for bug #23616: Week() changed behaviour between 5.0.22 and 5.0.24
    - result adjusted.
mysql-test/r/func_time.result:
  Fix for bug #23616: Week() changed behaviour between 5.0.22 and 5.0.24
    - test result.
mysql-test/t/func_time.test:
  Fix for bug #23616: Week() changed behaviour between 5.0.22 and 5.0.24
    - test case.
sql-common/my_time.c:
  Fix for bug #23616: Week() changed behaviour between 5.0.22 and 5.0.24
    - consider '.' as an acceptable separator for dates like YYYYYMMDDHHMMSS.XXXXXX