refactor(port): delete unused Memory_Resource::is_equal

src/quick-lint-js/container/linked-bump-allocator.h

@@ -244,10 +244,6 @@ class Linked_Bump_Allocator final : public Memory_Resource {
     this->deallocate_bytes(p, bytes);
   }
 
-  bool do_is_equal(const Memory_Resource& other) const override {
-    return this == static_cast<const Linked_Bump_Allocator*>(&other);
-  }
-
  private:
   struct alignas(maximum(alignment, alignof(void*))) Chunk_Header {
     explicit Chunk_Header(Chunk* previous) : previous(previous) {}

src/quick-lint-js/port/memory-resource.cpp

@@ -29,10 +29,6 @@ class New_Delete_Resource_Impl : public Memory_Resource {
     ::operator delete(p);
 #endif
   }
-
-  bool do_is_equal(const Memory_Resource& other) const override {
-    return this == static_cast<const New_Delete_Resource_Impl*>(&other);
-  }
 };
 }
 

src/quick-lint-js/port/memory-resource.h

@@ -19,15 +19,10 @@ class Memory_Resource {
     return this->do_deallocate(p, bytes, alignment);
   }
 
-  bool is_equal(const Memory_Resource& other) const {
-    return this->do_is_equal(other);
-  }
-
  protected:
   virtual void* do_allocate(std::size_t bytes, std::size_t alignment) = 0;
   virtual void do_deallocate(void* p, std::size_t bytes,
                              std::size_t alignment) = 0;
-  virtual bool do_is_equal(const Memory_Resource& other) const = 0;
 };
 
 // Like std::pmr::new_delete_resource.

test/quick-lint-js/tracking-memory-resource.h

@@ -34,11 +34,6 @@ class Tracking_Memory_Resource : public Memory_Resource {
     }
   }
 
-  bool do_is_equal(const Memory_Resource&) const override {
-    QLJS_UNIMPLEMENTED();
-    return false;
-  }
-
   Memory_Resource* underlying_memory_ = new_delete_resource();
 
   std::uint64_t allocated_bytes_ = 0;