xfstests: exclude largefs fill files from dump tests

xfstests: exclude largefs fill files from dump tests

The xfsdump/restore tests will see the space filling files and may
try to back them up and restore them, consuming huge amounts of time
to do (especially when diffing the results). Exclude the space
filling files by setting the no dump attributes on them and ensure
that xfsdump runs with the -e flag to exclude such files.

This also needs a dump filter addition to remove the output that
files were skipped, and to decrement the count of files processed by
xfsrestore because the inventory still includes excluded files.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Rich Johnston <rjohnston@sgi.com>
Signed-off-by: Rich Johnston <rjohnston@sgi.com>