RFR: 8191862: Warn about UseNUMA/UseLargePages only when using ParallelGC

[Per Liden]

Hi,

We currently warn about using UseAdaptiveSizePolicy and 
UseAdaptiveNUMAChunkSizing in combination with UseNUMA and 
UseLargePages. This warning is only relevant for ParallelGC, but we 
print it regardless of which GC has been selected.

Webrev: http://cr.openjdk.java.net/~pliden/8191862/webrev.0/
Bug: https://bugs.openjdk.java.net/browse/JDK-8191862

/Per