8167108: inconsistent handling of SR_lock can lead to crashes Summary: Add Thread Safe Memory Reclamation (Thread-SMR) mechanism. Reviewed-by: coleenp, dcubed, dholmes, eosterlund, gthornbr, kbarrett, rehn, sspitsyn, stefank Contributed-by: daniel.daugherty@oracle.com, erik.osterlund@oracle.com, robbin.ehn@oracle.com