RFR: Fix Clang build warnings

[Roman Kennke]

Am 02.02.2018 um 11:37 schrieb Aleksey Shipilev:
> http://cr.openjdk.java.net/~shade/shenandoah/build/macos-1/webrev.03/
> 
> These produce warnings for Clang, and thus break the build with Mac OS. Two cases were just
> rewritten for clarity. The change in loopPredicate.cpp picks up the correct assert that we have
> missed during the merge: http://hg.openjdk.java.net/shenandoah/jdk10/rev/1c9cefa2a443
> 
> Testing: hotspot_gc_shenandoah (Linux), build tests (by Lennart)
> 
> Thanks,
> -Aleksey
> 

Looks good.