kqueue tests: Re-enable kqueue proc tests

- Some EVFILT_PROC bugs were fixed around the time that the tests were
  disabled.
- I can't reproduce any failures locally.
- Jenkins logs referenced from the PR are gone, so let's re-enable the
  tests and see whether a problem persists.

PR:		233586
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation

tests/sys/kqueue/libkqueue/kqueue_test.sh

@@ -1,11 +1,8 @@
 #!/bin/sh
 # $FreeBSD$
 
-# Temporarily disable evfilt_proc tests: https://bugs.freebsd.org/233586
-skip="--no-proc"
-
 i=1
-"$(dirname $0)/kqtest" ${skip} | while read line; do
+"$(dirname $0)/kqtest" | while read line; do
 	echo $line | grep -q passed
 	if [ $? -eq 0 ]; then
 		echo "ok - $i $line"