[regexp] Ensure there are no shape changes on the fast path

src/builtins/builtins-regexp.h

Index: src/builtins/builtins-regexp.h
diff --git a/src/builtins/builtins-regexp.h b/src/builtins/builtins-regexp.h
index f14a41e051fbd4aba01aae6f7f14dd5227a2980a..7527fc193d5eab3b0720d40394f1c652724a0495 100644
--- a/src/builtins/builtins-regexp.h
+++ b/src/builtins/builtins-regexp.h
@@ -19,8 +19,8 @@ class RegExpBuiltinsAssembler : public CodeStubAssembler {
   explicit RegExpBuiltinsAssembler(CodeAssemblerState* state)
       : CodeStubAssembler(state) {}
 
-  void BranchIfFastRegExp(Node* const context, Node* const map,
-                          Label* const if_isunmodified,
+  void BranchIfFastRegExp(Node* const context, Node* const object,
+                          Node* const map, Label* const if_isunmodified,
                           Label* const if_ismodified);
 
  protected:
@@ -50,9 +50,10 @@ class RegExpBuiltinsAssembler : public CodeStubAssembler {
                              char const* method_name);
 
   // Analogous to BranchIfFastRegExp, for use in asserts.
-  Node* IsFastRegExpMap(Node* const context, Node* const map);
+  Node* IsFastRegExpMap(Node* const context, Node* const object,
+                        Node* const map);
 
-  Node* IsInitialRegExpMap(Node* context, Node* map);
+  Node* IsInitialRegExpMap(Node* context, Node* object, Node* map);
   void BranchIfFastRegExpResult(Node* context, Node* map,
                                 Label* if_isunmodified, Label* if_ismodified);