btrfs/130: remove the dangerous group

btrfs/130: remove the dangerous group

As of the linux kernel commit fd0ddbe2509568 ("Btrfs: send, skip
backreference walking for extents with many references"), the test is no
longer dangerous and it's fast (takes 1 to 2 seconds on a modest vm with
a debug kernel). Therefore remove it from the dangerous group and add it
to the auto and quick groups as well.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>