8017070: G1: assert(_card_counts[card_num] <= G1ConcRSHotCardLimit) failed Summary: The assert is invalid when a card is being refined by two different threads and its count crosses the hot threshold - the refinement count will be updated once by each thread triggering the assert. Remove the assert and update the count using a bounded expression. Reviewed-by: jmasa, tamao, brutisso

project=jdk8