Fixes #13779. Remove nodes in document order (uses for loop matching empty()).
Loop cleanup

Signed-off-by: Rick Waldron <waldron.rick@gmail.com>
Fix #13483. Let slideDown() work after stop(). Close gh-1205.
Fix #12838: hook point for non-jQuery.ajax synchronous script fetch/execute in domManip. Close gh-1051.
Followup #13779: Backwards-compatible unit test
(cherry picked from commit 12a101729086ec1f9b8b029cd66971c11959bc33)
Refactor code in effects to use data_priv. Re- Close gh-1244.