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

8014022: G1: Non Java threads should lock the shared SATB queue lock without safepoint checks. Reviewed-by: tschatzl, brutisso, jmasa, ysr Contributed-by: per.liden@oracle.com