2178143: JVM crashes if the number of bound CPUs changed during runtime Summary: Supply a new flag -XX:+AssumeMP to workaround the problem. With the flag is turned on, assume VM run on MP platform so is_MP() will return true that sync calls will not skip away. Reviewed-by: dholmes, acorn, dcubed, jmasa Contributed-by: yumin.qi@oracle.com