Roll back all step-in-fix-related changes

src/x64/debug-x64.cc

Index: src/x64/debug-x64.cc
diff --git a/src/x64/debug-x64.cc b/src/x64/debug-x64.cc
index 2aa77e7752e02ae87b09f3e7bdfffca9a96cd21e..96592548ef7a536861ce7022192dc918aae19cc3 100644
--- a/src/x64/debug-x64.cc
+++ b/src/x64/debug-x64.cc
@@ -213,10 +213,9 @@ void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
 #undef __
 
 
-Object** Debug::SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
-                                       Handle<Code> code) {
+void Debug::SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
+                                   Handle<Code> code) {
   UNREACHABLE();
-  return NULL;
 }
 const int Debug::kFrameDropperFrameSize = -1;