Consolidate curFrame fields in thread storage

We ended up with two locations in the Thread structure for saved
Dalvik frame pointer.  This change consolidates them.

Change-Id: I78f288e4e57e232f29663be930101e775bfe370f
diff --git a/vm/alloc/Visit.cpp b/vm/alloc/Visit.cpp
index b329595..7f949f6 100644
--- a/vm/alloc/Visit.cpp
+++ b/vm/alloc/Visit.cpp
@@ -87,7 +87,7 @@
     assert(thread != NULL);
     u4 threadId = thread->threadId;
     const StackSaveArea *saveArea;
-    for (u4 *fp = (u4 *)thread->curFrame;
+    for (u4 *fp = (u4 *)thread->interpSave.curFrame;
          fp != NULL;
          fp = (u4 *)saveArea->prevFrame) {
         Method *method;