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

[Roland Westrelin]

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.