8171417: post jigsaw review cleanup in the jtreg jvmti tests Summary: fix the function throw_exc() in several jvmti tests to return void Reviewed-by: dsamersoff, hseigel

^build/
^dist/
^.idea/
nbproject/private/
^webrev
^.src-rev$
^.jib/
.DS_Store
.metadata/
.recommenders/