6673853: LegacyIntrospectorTest is testing an old deprecated com.sun API not present in OpenJDK.
Summary: Removed test from open test suite - the corresponding deprecated legacy API is not in open source tree
Reviewed-by: emcmanus
6714406: Node::dominates() does not always check for TOP
Summary: Add missed checks for TOP and missed checks for non-dominating cases
Reviewed-by: rasbold, jrose, never