8233997: Some members of HeapRegion are not cleared in HeapRegion::hr_clear()
Reviewed-by: sjohanss, sangheki
/build/
/dist/
/.idea/
nbproject/private/
/webrev
/.src-rev
/.jib/
.DS_Store
.metadata/
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test/nashorn/script/external
test/nashorn/lib
NashornProfile.txt
**/JTreport/**
**/JTwork/**