[8u20] RFR (S): 8050050: [TESTBUG] compiler/stable tests fail because WB API is not implemented

[Vladimir Ivanov]

http://cr.openjdk.java.net/~vlivanov/8050050/webrev.00
https://bugs.openjdk.java.net/browse/JDK-8050050

8038756 wasn't backported to 8u20, so WB::get/setVMFlag aren't available 
there. The fix for 8u20 is to rewrite configuration logic detection 
using JMX.

Testing: affected tests.

Thanks!

Best regards,
Vladimir Ivanov