ext4/053: update the test_dummy_encryption tests

ext4/053: update the test_dummy_encryption tests

Kernel commit 5f41fdaea63d ("ext4: only allow test_dummy_encryption when
supported") tightened the requirements on when the test_dummy_encryption
mount option is accepted.  Update ext4/053 accordingly.

Move the test cases to later in the file to group them with the other
test cases that use do_mkfs to add custom mkfs options instead of using
the "default" filesystem that the test creates at the beginning.

Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>