Cleanup the way the debugger stores live registers when entering at a break

Cleanup the way the debugger stores live registers when entering at a break

The live registers are now only stored to the expression stack with the non pointer values being stored as smis (on the 32-bit platforms these values are assumed to be 31-bit max).

This makes the CEntryStub entry/exit code much simpler, and there is no longer any need for a mode (debug or normal) on it.

Fix a missing live register when breaking at ARM keyed load.
Review URL: http://codereview.chromium.org/3141047

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5358 ce2b1a6d-e550-0410-aec6-3dcde31c8c00