web_ui: drop internal hash code library (#53783)

We moved to dart:core Object functions a while ago

Author: kevmoo

ci/licenses_golden/licenses_flutter

@@ -42781,7 +42781,6 @@ ORIGIN: ../../../flutter/lib/web_ui/lib/canvas.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/channel_buffers.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/compositing.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/geometry.dart + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/lib/web_ui/lib/hash_codes.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/initialization.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/key.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/lerp.dart + ../../../flutter/LICENSE
@@ -45656,7 +45655,6 @@ FILE: ../../../flutter/lib/web_ui/lib/canvas.dart
 FILE: ../../../flutter/lib/web_ui/lib/channel_buffers.dart
 FILE: ../../../flutter/lib/web_ui/lib/compositing.dart
 FILE: ../../../flutter/lib/web_ui/lib/geometry.dart
-FILE: ../../../flutter/lib/web_ui/lib/hash_codes.dart
 FILE: ../../../flutter/lib/web_ui/lib/initialization.dart
 FILE: ../../../flutter/lib/web_ui/lib/key.dart
 FILE: ../../../flutter/lib/web_ui/lib/lerp.dart

lib/web_ui/lib/hash_codes.dart

@@ -21,7 +21,6 @@ part 'canvas.dart';
 part 'channel_buffers.dart';
 part 'compositing.dart';
 part 'geometry.dart';
-part 'hash_codes.dart';
 part 'initialization.dart';
 part 'key.dart';
 part 'lerp.dart';