RFR: 8225016: Dead code due to VMOperationQueue::add() always returning true

[Patricio Chilano]

Hi all,

Could you review this small patch? It removes dead code in vmThread code.

Webrev:
http://cr.openjdk.java.net/~pchilanomate/8225016/v01/webrev/
Bug:
https://bugs.openjdk.java.net/browse/JDK-8225016

Passed tiers1-2 in mach5.

Thanks!
Patricio