RFR: 8144630: Use PrivilegedAction to create Thread in Marlin RendererStats

[Laurent Bourgès]

Please review this 3rd patch to backport the Marlin renderer from jdk9.

JBS: https://bugs.openjdk.java.net/browse/JDK-8144630
patch:
http://cr.openjdk.java.net/~lbourges/marlin8u/marlin-8.03/m03.8144630.patch
webrev:
http://cr.openjdk.java.net/~lbourges/marlin8u/marlin-8.03/m03.8144630-webrev/
unshuffled patch:
http://cr.openjdk.java.net/~lbourges/marlin8u/marlin-8.03/unshuffled/8-m03.8144630.patch

Changes in RendererStats:
* Fixed import:
-+import sun.awt.util.ThreadGroupUtils;
++import sun.misc.ThreadGroupUtils;
* Fixed indentation / chunks
<http://cr.openjdk.java.net/~lbourges/marlin8u/marlin-8.03/>

Best regards,
Laurent