Fixes issue 851
Fixes issue 851

Extend earlier cross-frame retaddr transition work (i#1436, i#703) by
checking the transition from the first scanned frame to the top frame
(i.e., cur pc).

Explicitly do not check cross-frame targeting when the top frame is a
replaced routine.

SVN-Revision: 1744

sigma-random/drmemory,code4bones/drmemory,code4bones/drmemory,sigma-random/drmemory,LohithBlaze/drmemory,sigma-random/drmemory,code4bones/drmemory,code4bones/drmemory,sigma-random/drmemory,LohithBlaze/drmemory,LohithBlaze/drmemory,LohithBlaze/drmemory,code4bones/drmemory,sigma-random/drmemory,LohithBlaze/drmemory