tests: warn about xpass/xfail marked tests

With the two recent unix socket test patches to mark dgram tests as
failing but expected to pass, I realized that there's no indication
in the output that there are current expected failures (except for
the single corefile test expected failure)[0]. This patch attempts to
remedy that by emitting the x-type plus the test description for each
test that is marked as such. I've set it to always emit these results.

[0] The test infrastructure does give an alert if there is a test that
    has been marked xpass or xfail but has started behaving correctly.

Signed-off-by: Steve Beattie <steve@nxnw.org>
Acked-by: Tyler Hicks <tyhicks@canonical.com>

tests/regression/apparmor/prologue.inc

@@ -250,7 +250,10 @@ checktestfg()
 		fi
 	fi
 
-	if [ -n "$VERBOSE" ]; then
+	# warn about expected failures
+	if [ -n "${_known}" ] ; then
+		echo "x${_pfmode}: ${_testdesc}"
+	elif [ -n "$VERBOSE" ]; then
 		echo "ok: ${_testdesc}"
 	fi
 }