RFR(S): 8240335: C2: assert(found_sfpt) failed: no node in loop that's not input to safepoint

[Roland Westrelin]

Thanks for reviewing this.

> I think in wait_for_region_igvn() method it should be '} else if () {' if 'delay' set to 'true' to avoid additional checks:
>
> +        delay = true;
> +      } else if(...
>
>
> It is also better to use faster method worklist.member() instead of worklist.contains().

Right. Do we want to overload contains() in Unique_Node_List to catch
such a mistake?

http://cr.openjdk.java.net/~roland/8240335/webrev.01/

Roland.