[csa][cleanup] Remove unused TaggedToFastJSArray method

Bug: v8:7703
Change-Id: I685ad610e29f277381103c4be2c374bf0b7336ef
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2294979
Auto-Submit: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68841}

src/codegen/code-stub-assembler.h

@@ -427,14 +427,6 @@ class V8_EXPORT_PRIVATE CodeStubAssembler
     return UncheckedCast<Uint16T>(Int32Constant(t));
   }
 
-  TNode<JSArray> TaggedToFastJSArray(TNode<Context> context,
-                                     TNode<Object> value, Label* fail) {
-    GotoIf(TaggedIsSmi(value), fail);
-    TNode<HeapObject> heap_object = CAST(value);
-    GotoIfNot(IsFastJSArray(heap_object, context), fail);
-    return UncheckedCast<JSArray>(heap_object);
-  }
-
   TNode<JSDataView> HeapObjectToJSDataView(TNode<HeapObject> heap_object,
                                            Label* fail) {
     GotoIfNot(IsJSDataView(heap_object), fail);