RFR: 8076421: Fix Zero Interpreter bugs in class redefinition and template interpreter changeS

[Coleen Phillimore]

Summary: metadata_do walking interpreted frames was wrong and 
generate_Reference_get is not necessarily an accessor method.

Tested internal and test/runtime/RedefineTests with fix.   Also tested 
class redefinition tests with linux x64 since there were shared code 
changes.

open webrev at http://cr.openjdk.java.net/~coleenp/8076421/
bug link https://bugs.openjdk.java.net/browse/JDK-8076421

Thanks,
Coleen