RFR (S) JDK-8178712: ResourceMark may be missing inside initialize_[vi]table

[Lois Foltan]

Please review this clean up change to correctly set ResourceMark from 
within klassVtable::initialize_vtable() and 
klassItable::initialize_itable() when applicable, instead of having all 
instances of calls to these two methods establish a ResourceMark 
unnecessarily prior to.

open webrev at http://cr.openjdk.java.net/~lfoltan/bug_jdk8178712/
bug link at https://bugs.openjdk.java.net/browse/JDK-8178712

Testing: hs-tier1-3, jdk-tier1-3 (complete)
                hs-tier4-5 (in progress)

Thanks,
Lois