RFR: sh/jdk11 assert failure because IfNode input is a Phi

[Roman Kennke]

I have tested the failing test, run all of specjvm with verification,
and hotspot_gc_shenandoah. Looks all good. Please push it to sh/jdk11
and under proper ID to jdk/jdk (I guess we need to rubber stamp it again).

Thanks,
Roman

> http://cr.openjdk.java.net/~roland/shenandoah/LRBafterCallUseBool/webrev.00/
> 
> Input 1 of an IfNode must not be a Phi node so when cloning an LRB
> that's right after a call in the exception and fallthrough paths, we
> must make sure to clone the BoolNode and CmpNode that feed into an
> IfNode and not introduce a Phi.
> 
> This fix also applies to upstream and will need to be fixed there.
> 
> Roland.
>