RFR: : vdefault / vwithfield

[frederic parain]

Summary:
   - add vdefault and vwithfield to runtime ad interpreter
   - some cleanup / simplification in vnew and vgetfield
   - some naming cleanup
   - fix cpCache for vgetfield and vwithfield

http://jurassic.us.oracle.com/~fparain/Webrevs/mvt-bytecodes/webrev.01/

Thanks,

Fred