API change in StackVisitor::GetVReg*.

- Remove GetVReg() and SetVReg() that were expecting to always succeed.
- Change Quick-only methods to take a FromQuickCode suffix.
- Change deopt to use dead values when GetVReg does not succeed:
  the optimizing compiler will not have a location for uninitialized
  Dex registers and potentially dead registers.

Change-Id: Ida05773a97aff8aa69e0caf42ea961f80f854b77
7 files changed