RFR (S) 8242229: Shenandoah: inline ShenandoahHeapRegion liveness-related methods

[Roman Kennke]

Ok. Yes, explicit includes is always preferred if it's used in the
compilation unit.

Thanks,
Roman

> RFE:
>   https://bugs.openjdk.java.net/browse/JDK-8242229
> 
> Webrev:
>   https://cr.openjdk.java.net/~shade/8242229/webrev.01/
> 
> These methods are used on critical paths during choosing the collection set, and should be inlined.
> 
> While shenandoahHeapRegion.inline.hpp is transitively included by shenandoahHeap.inline.hpp, which
> pretty much every other compilation unit includes, I still opted to include it directly in the
> affected compilation units.
> 
> Testing: hotspot_gc_shenadoah, benchmarks, eyeballing disassemblies, non-PCH {slowdebug,
> fastdebug,release} builds
>