7048782: CMS: assert(last_chunk_index_to_check<= last_chunk_index) failed: parCardTableModRefBS.cpp:359 Summary: The LNC array is sized before the start of a scavenge, while the heap may expand during a scavenge. With CMS, the last block of an arbitrary suffice of the LNC array may expand due to coalition with the expansion delta. We now take care not to attempt access past the end of the LNC array. LNC array code will be cleaned up and suitably encapsulated as part of the forthcoming performance RFE 7043675. Reviewed-by: brutisso