[rfc] ``pc'' -> resume_addr?

[Andrew Cagney]

>     frame->pc    ==> frame->resume_addr
> 
> This, I think, should change.  I'm 99% sure that this isn't the hardware PC but rather the continue address for the frame (but notice I'm not 100% sure thanks to its poor definition).

Hmm, there is another approach here.  As with frame_base() from my 
previous post, a more dynamic:

	frame_resume_addr (frame)

that would let the ISA code compute it on demand using the frame's 
register information - in theory frame->pc could be removed.

Andrew