RFR: Collapse little assert blocks into big one

[Roman Kennke]

As subject says:

http://cr.openjdk.java.net/~rkennke/assertblock/webrev.00/

I think they should be semantically equivalent.

This here seems slightly odd:

assert(u->as_Mem()->raw_adr_type() == TypeOopPtr::BOTTOM, "bad slice");
u->as_Mem()->set_raw_adr_type(TypeRawPtr::BOTTOM);


Ok?

Roman