[8u76] 8029630: Thread id should be displayed as hex number in error report

[david buck]

Hi!

Please approve this trivial backport (applies as-is) to jdk8u-dev.

jbs bug: https://bugs.openjdk.java.net/browse/JDK-8029630
jdk9 changeset: 
http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/f147f5db527c
jdk9 review thread: 
http://mail.openjdk.java.net/pipermail/hotspot-dev/2015-April/017832.html

Cheers,
-Buck