RFR: some more jdk11 cleanup

[Roman Kennke]

That's great! Thanks!

Roman


> 
> A single line backport from jdk/jdk:
> 
> 4171       // Verification can't be applied to fully built strip mined loops
> 4172       head->as_Loop()->outer_loop_end()->in(1)->find_int_con(-1) == 0) {
> 
> makes a bunch of shared code changes useless:
> 
> http://cr.openjdk.java.net/~roland/shenandoah/jdk11-cleanup2/webrev.00/
> 
> Roland.
>