generic: xattr enospc cleanup test

XFS had a regression where inode reclaim in the unlink codepath would
not correctly tear down extended attribute forks where no xattr extents
are present. Add a generic test to create this condition.

The test sets extended attributes on a series of files under ENOSPC
conditions and then verifies that the files can be removed without
syslog warnings or errors.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

common/rc

@@ -2995,6 +2995,7 @@ _check_dmesg()
 	     -e "BUG:" \
 	     -e "Oops:" \
 	     -e "possible recursive locking detected" \
+	     -e "Internal error" \
 	     $seqres.dmesg
 	if [ $? -eq 0 ]; then
 		echo "_check_dmesg: something found in dmesg (see $seqres.dmesg)"