MFC r313733:

MFC r313733:

sleepq_catch_signals: do thread suspension before signal check

Since locks are dropped when a thread suspends, it's possible for another
thread to deliver a signal to the suspended thread. If the thread awakens from
suspension without checking for signals, it may go to sleep despite having
a pending signal that should wake it up. Therefore the suspension check is
done first, so any signals sent while suspended will be caught in the
subsequent signal check.

Sponsored by:	Dell EMC

git-svn-id: svn://svn.freebsd.org/base/stable/10@315345 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f