generic: fix insert test group associations

generic: fix insert test group associations

The change makes one-in-one correspondence between generic tests in
'insert' test group and tests with $(_require_xfs_io_command "finsert")
runtime check:

* generic/348 -- insert group association is removed,
* generic/458 -- insert group association is added.

The intention of the change is to get better summarized association
between tests and test groups to be able to operate with test groups
in a better way.

Signed-off-by: Vladimir Zapolskiy <vladimir@tuxera.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>