factor out "ReloadContextFromFrame"

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index 3381a5b7b6cd0d2d3997451a162bb01eb91d008d..48503208cb18863018b06c23d676ae1a0ceb9801 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -1145,6 +1145,9 @@ class MacroAssembler: public Assembler {
   //   index - holds the overwritten index on exit.
   void IndexFromHash(Register hash, Register index);
 
+  // Reload the context register from a standard stack frame.
+  void ReloadContextFromFrame();
+
   // Find the function context up the context chain.
   void LoadContext(Register dst, int context_chain_length);