Add missing HandleMarks

The review for JDK-8304147 pointed out that the top-level HandleMark in dump_for_exit (added to replace the previous coverage from a HandleMarkCleaner in JVM_ENTRY) was not in the right place as no Handles were being used there. Removing that HM and fixing up the ensuing failures led to a set of fixes where HM's were missing at the place of Handle usage.