common/filter: extend _filter_xfs_io to match -nan

common/filter: extend _filter_xfs_io to match -nan

When run on ext4 with sufficiently fast x86_64 hardware, generic/130
sometimes fails because xfs_io can report rate values as -nan:
0.000000 bytes, 0 ops; 0.0000 sec (-nan bytes/sec and -nan ops/sec)

_filter_xfs_io matches the strings 'inf' or 'nan', but not '-nan'.  In
that case it fails to convert the actual output to a normalized form
matching generic/130's golden output.  Extend the regular expression
used to match xfs_io's output to fix this.

Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>