6957080: MethodComparator needs stress testing
Summary: Add a stress-test flag for running MethodComparator over many inputs. Fix bugs that crop up.
Reviewed-by: kvn
6957004: MethodComparator uses the wrong CP index accessor
Summary: Change two uses of get_index_u2 to get_index_u2_cpcache; also tweak some debugging print functions
Reviewed-by: kvn