[12] RFR (T): 8146090: java/lang/ref/ReachabilityFenceTest.java fails with -XX:+DeoptimizeALot

[Vladimir Ivanov]

http://cr.openjdk.java.net/~vlivanov/8146090/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-8146090

The test doesn't work with -XX:+DeoptimizeALot: the test expects 
execution to continue in generated code after System.gc() call, but JVM 
constantly deoptimizes it at that point in -XX:+DeoptimizeALot mode, so 
execution continues in interpreter and it breaks the invariant the test 
checks.

The fix is to disable executing the test with -XX:+DeoptimizeALot.

Testing: manually verified that the test isn't executed when 
-XX:+DeoptimizeALot is specified.

Best regards,
Vladimir Ivanov