xfs/43[4-6]: implement impatient module reloading

xfs/43[4-6]: implement impatient module reloading

These three tests try to reload the xfs module as a cheap way to detect
leaked inode and dquot objects when the slabs for those object are torn
down during rmmod.  Removal might not succeed, and we don't really care
for that case because we still want to exercise the log recovery code.

However, if (say) the root filesystem is xfs, then removal will never
succeed.  There's no way that waiting 50 seconds(!) per test is going
to change that.  Add a silly helper to do it fast or go home.

Reported-by: sandeen@sandeen.net
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>