Add several test scripts wrapping test_workqueue

This is a fairly easy way for us to get our test coverage up on
compat_threads.c and workqueue.c -- I already implemented these
tests, so we might as well enable them.

src/test/test_workqueue_socketpair.sh

@@ -0,0 +1,4 @@
+#!/bin/sh
+
+${builddir:-.}/src/test/test_workqueue \
+	   --no-eventfd2 --no-eventfd --no-pipe2 --no-pipe