[9] RFR (XS): 8151623: Zap freed Metaspace chunks in non-product binaries

[Vladimir Ivanov]

http://cr.openjdk.java.net/~vlivanov/8151623/webrev.00
https://bugs.openjdk.java.net/browse/JDK-8151623

Zap freed Metaspace chunks in non-product binaries to catch stray 
accesses to unloaded classes.

Testing: JPRT, RBT (in progress): hotspot/test:hotspot_all, 
jdk/test:tier1 & tier2, vm.parallel_class_loading.testlist, 
vm.gc.testlist, BigApps w/ fastdebug binaries.

Thanks!

Best regards,
Vladimir Ivanov