RFR(XS): 8192908: -XX:+UseCountedLoopSafepoints alone doesn't disable strip mining with G1

[Roland Westrelin]

http://cr.openjdk.java.net/~roland/8192908/webrev.00/

Running java -XX:+UseCountedLoopSafepoints causes a message to be
printed:

warning: When counted loop safepoints are enabled, LoopStripMiningIter must be at least 1 (a safepoint every 1 iteration): setting it to 1

But the G1 specific code sets LoopStripMiningIter to 1000. This change
makes sure that -XX:+UseCountedLoopSafepoints disables loop strip
mining.

Roland.