8183039: Re-examine methodHandle methods uninlined by 8144256
Summary: Add more const references so out-of-line methodHandle destructor and copy ctor called infrequently
Reviewed-by: hseigel, redestad

6378256: Performance problem with System.identityHashCode in client compiler
Summary: Enabled C1 optimization to try pull out hashCode from object header, before calling into the VM.
Reviewed-by: dlong, roland, thartmann
Contributed-by: Rahul Raghavan <rahul.v.raghavan@oracle.com>