Frame layout change

This CL slightly changes the frame layout to remove an old unnecessary
slot, allow for the inclusion of compiler-generated temps and
unifies all variable offset calculation into a single function shared
by the compilers and the runtime system.

   o Update the GetVRegOffset function in stack.cc to understand the
     new layout.

   o Remove compiler-private offset calculation code and route
     everything through the shared GetVRegOffset in thread.cc.

   o Remove "filler word" that existed immediately after the last
     Dalvik local.  This was there to address an initial concern that
     I had about a single argument register being reused later as a
     long.  Now convinced that it won't happen.

   o Extend the old "padding" region to include compiler-created temps
     that can appear to the rest of the rest of the system as
     Dalvik registers.  The new temps will have Dalvik register numbers
     of -2 and lower.

   o Treat Method* for the current method as a special Dalvik register
     denoted by reg number -1.

Change-Id: I5b5f3aef9c6a01d3a647ced6ec06981ed228c785
diff --git a/src/compiler/codegen/RallocUtil.cc b/src/compiler/codegen/RallocUtil.cc
index cfda721..b5ebf65 100644
--- a/src/compiler/codegen/RallocUtil.cc
+++ b/src/compiler/codegen/RallocUtil.cc
@@ -1217,8 +1217,8 @@
 /* Returns sp-relative offset in bytes for a VReg */
 extern int oatVRegOffset(CompilationUnit* cUnit, int vReg)
 {
-    return (vReg < cUnit->numRegs) ? cUnit->regsOffset + (vReg << 2) :
-            cUnit->insOffset + ((vReg - cUnit->numRegs) << 2);
+    return Frame::GetVRegOffset(cUnit->code_item, cUnit->coreSpillMask,
+                                cUnit->fpSpillMask, cUnit->frameSize, vReg);
 }
 
 /* Returns sp-relative offset in bytes for a SReg */