xfs: New _require_* tests for CRC enabled filesystems

xfs: New _require_* tests for CRC enabled filesystems

CRCs always enabled 32 bit project inodes and attr2 formats, hence
they cannot be turned off. Add new require rules for the tests that
require attr and 16 bit project IDs so these tests are avoided on
CRC enabled filesystems.

Also, add a xfs_db write check so that we can avoid tests that are
dependent on xfs_db modifying filesystem structures as they will
fail on CRC enabled filessystems right now. This is just temporary
until full write xfs_db support is available.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Rich Johnston <rjohnston@sgi.com>