Move nonNull and alwaysNull flags up to AbstractPointerStamp.
Use correct LIRKind in HSAIL metaspace pointer compression/uncompression op.
Use floating node for casting between metaspace pointers and words.
Introduce StampProvider to support different stamps for metadata on different VMs.
Use StampProvider to create platform dependent stamps for LoadHub and LoadMethod nodes.
Create separate stamps for Klass* and Method*, and make them hotspot specific.
Move raw memory access operations to a separate interface.
Move HotSpot specific functionality to new subinterface of ConstantReflectionProvider.
mx build: set initial heap size explicitly