[interpreter] Add a fast path for dynamic local load

src/interpreter/interpreter-assembler.h

Index: src/interpreter/interpreter-assembler.h
diff --git a/src/interpreter/interpreter-assembler.h b/src/interpreter/interpreter-assembler.h
index 5ae80fdd739f01a80dbd09cf0f16c1b7cfefd11f..9dda20af4877ac58fbafba90b0d91f0578d8d44c 100644
--- a/src/interpreter/interpreter-assembler.h
+++ b/src/interpreter/interpreter-assembler.h
@@ -56,10 +56,15 @@ class InterpreterAssembler : public CodeStubAssembler {
   compiler::Node* GetContext();
   void SetContext(compiler::Node* value);
 
-  // Context at |depth| in the context chain starting at |context|
+  // Context at |depth| in the context chain starting at |context|.
   compiler::Node* GetContextAtDepth(compiler::Node* context,
                                     compiler::Node* depth);
 
+  // Goto the given |target| if the context chain starting at |context| has any
+  // extensions up to the given |depth|.
+  void GotoIfHasContextExtensionUpToDepth(compiler::Node* context,
+                                          compiler::Node* depth, Label* target);
+
   // Number of registers.
   compiler::Node* RegisterCount();