selftests: ublk: fix test_stripe_04

[ Upstream commit 72070e57b0a518ec8e562a2b68fdfc796ef5c040 ]

Commit 57ed58c13256 ("selftests: ublk: enable zero copy for stripe target")
added test entry of test_stripe_04, but forgot to add the test script.

So fix the test by adding the script file.

Reported-by: Uday Shankar <ushankar@purestorage.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Uday Shankar <ushankar@purestorage.com>
Link: https://lore.kernel.org/r/20250404001849.1443064-1-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>