[compiler] Remove dead method declarations

Tbr: neis@chromium.org
Bug: v8:7790
Change-Id: Iaa094977b3c1099880ead9819df8418bc85e3dde
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2947416Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75035}

src/compiler/heap-refs.h

@@ -168,7 +168,6 @@ class V8_EXPORT_PRIVATE ObjectRef {
   Handle<Object> object() const;
 
   bool equals(const ObjectRef& other) const;
-  bool ShouldHaveBeenSerialized() const;
 
   bool IsSmi() const;
   int AsSmi() const;
@@ -979,7 +978,6 @@ class JSTypedArrayRef : public JSObjectRef {
 
   void Serialize();
   bool serialized() const;
-  bool ShouldHaveBeenSerialized() const;
 
   HeapObjectRef buffer() const;
 };