Task 6:
We can find the .frm type of file. If it is sequence then is_sequence
passed to dd_frm_type() will be true. Since there is already a check
to give error message if we trigger is on temporary table or view, an
additional condition is added to check if .frm is sequence
(is_sequence==true) and error message is changed to show
"Trigger's '%-.192s' is view, temporary table or sequence" instead of
"Trigger's '%-.192s' is view or temporary table".
In main.index_merge_myisam we remove the test that was added in
commit a2d24def8c because
it duplicates the test case that was added in
commit 5af12e4635.