RFR: Clean up leftovers from type.cpp

[Roman Kennke]

This went out too early. I meant to say that I wanted to do this cleanup
when I merged:

http://hg.openjdk.java.net/jdk/jdk/rev/6082c529aed8

but then forgot. We don't need this checks anymore because when we get
there it can't be Shenandoah barrier because of stricter check above:

-  if (_offset != 0) {
+  if (_offset > 0 || _offset == Type::OffsetTop || _offset ==
Type::OffsetBot) {


> http://cr.openjdk.java.net/~rkennke/cleanup-type-cpp/webrev.00/


Ok?

Roman