fstests: Add Log Attribute Replay test

fstests: Add Log Attribute Replay test

This patch adds tests to exercise the log attribute error
inject and log replay. These tests aim to cover cases where attributes
are added, removed, and overwritten in each format (shortform, leaf,
node). Error inject is used to replay these operations from the log.

dchinner: sanitise md5sum input to just attr values.
dchinner: correct md5sums.
dchinner: ensure replace tests use different values so recovery can
          determine the replace was replayed correctly.
dchinner: don't remove corpse in _cleanup - scratch devices don't
	  require cleanup, and if the test fails we want to leave
	  the broken state for post-mortem analysis.
dchinner: only run on v5 filesystems.

[zlang: restore the old value of /sys/fs/xfs/debug/larp]

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Zorro Lang <zlang@kernel.org>