RFR: Rename *_oop_static/oop_ref to *_forwarded

[Aleksey Shipilev]

http://cr.openjdk.java.net/~shade/shenandoah/bs-rename-resolve/webrev.01/

This renames a group of methods to *_forwarded, to reflect the intent better. "Static" is confusing,
because only tells about the function's static linkage, and not about the property of the oop being
resolved. "oop_ref" is confusing, because it looks like some other method exists, that deals with
something else (not "oop", and not "ref").

Testing: hotspot_gc_shenandoah

Thanks,
-Aleksey