7197269: NPG: FollowReferences has no ClassLoader -> Class link to follow
Summary: restore java/lang/ClassLoader.addClass() upcall
Reviewed-by: sspitsyn, dcubed, jmasa
7197906: BlockOffsetArray::power_to_cards_back() needs to handle > 32 bit shifts
Reviewed-by: brutisso, johnc, ysr
Contributed-by: Hal Mo <kungu.mjh@taobao.com>