RFR 8087315: SIGBUS error in nsk/jvmti/RedefineClasses/StressRedefine

[Coleen Phillimore]

Summary: Need to get source_file_name from the_class's constant pool not 
previous version constant pool

open webrev at http://cr.openjdk.java.net/~coleenp/8087315.01/
bug link https://bugs.openjdk.java.net/browse/JDK-8087315

Tested with added test (yay!), RBT (remote build and test), 
vm.redefine.testlist, jdk/test/java/lang/instrument and failing testcase 
1000 times (reproduced <400).

Thanks,
Coleen