RFR 9: 8150337 : sun/misc/SunMiscSignalTest.java failed intermittently

Please review a test update to skip tests using SIGINT, SIGTERM, and SIGHUP when run with those signals are ignored. For example, using nohup or trap in a shell. It also includes a small enhancement adding sun.misc.Signal.toString ease debugging. Webrev: http://cr.openjdk.java.net/~rriggs/webrev-nohup-8150337/index.html Thanks, Roger