check: ensure to suppress job status output

check: ensure to suppress job status output

Unexpected job status output by wait commands was observed on openSUSE
15.3 and it made some test cases fail. To avoid the job status output
during test case runs, ensure to turn off job control monitor in sub-
shell for test case runs.

Reported-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/linux-block/20220613151721.18664-1-jack@suse.cz/
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Tested-by: Jan Kara <jack@suse.cz>