[map] Remove unused function declaration

Change-Id: I4c86e7ff110b4457a4d52b66462b31b62b42473f
Reviewed-on: https://chromium-review.googlesource.com/1126891Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54250}

src/objects/map.h

@@ -922,10 +922,6 @@ class Map : public HeapObject {
                                            Handle<DescriptorArray> descriptors,
                                            Descriptor* descriptor, int index,
                                            TransitionFlag flag);
-  static V8_WARN_UNUSED_RESULT MaybeHandle<Map> TryReconfigureExistingProperty(
-      Handle<Map> map, int descriptor, PropertyKind kind,
-      PropertyAttributes attributes, const char** reason);
-
   static Handle<Map> CopyNormalized(Isolate* isolate, Handle<Map> map,
                                     PropertyNormalizationMode mode);