RFR 8u Backport: 8179515: Class java.util.concurrent.ThreadLocalRandom fails to Initialize when using SecurityManager

[David Holmes]

The existing code in 8u was a little different to 9, but the new code is 
identical (other than package names):

webrev: http://cr.openjdk.java.net/~dholmes/8179515/webrev.8u/
Bug: https://bugs.openjdk.java.net/browse/JDK-8179515
9 changeset: http://hg.openjdk.java.net/jdk9/dev/jdk/rev/bb4cdc198dc0
9 review thread: 
http://mail.openjdk.java.net/pipermail/core-libs-dev/2017-May/047615.html

Thanks,
David