[turbofan]: Elide extra move when accessing stack or frame register

src/x64/frames-x64.cc

Index: src/x64/frames-x64.cc
diff --git a/src/x64/frames-x64.cc b/src/x64/frames-x64.cc
index 11db5b9ed60bf896a5c63f44bb1709191eb206bf..5360d3eb16a572ff2dccc06756e5aef00cd9b241 100644
--- a/src/x64/frames-x64.cc
+++ b/src/x64/frames-x64.cc
@@ -15,7 +15,8 @@ namespace v8 {
 namespace internal {
 
 
-Register JavaScriptFrame::fp_register() { return rbp; }
+Register StandardFrame::sp_register() { return rsp; }
+Register StandardFrame::fp_register() { return rbp; }
 Register JavaScriptFrame::context_register() { return rsi; }
 Register JavaScriptFrame::constant_pool_pointer_register() {
   UNREACHABLE();