Drop deprecated hash_code functions (flutter#54000)

Fixes flutter#151679

Author: kevmoo

ci/licenses_golden/licenses_flutter

@@ -42703,7 +42703,6 @@ ORIGIN: ../../../flutter/lib/ui/experiments/setup_hooks.dart + ../../../flutter/
 ORIGIN: ../../../flutter/lib/ui/experiments/ui.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/ui/floating_point.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/ui/geometry.dart + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/lib/ui/hash_codes.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/ui/hooks.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/ui/io_manager.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/ui/io_manager.h + ../../../flutter/LICENSE
@@ -42866,7 +42865,6 @@ 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
@@ -45583,7 +45581,6 @@ FILE: ../../../flutter/lib/ui/experiments/setup_hooks.dart
 FILE: ../../../flutter/lib/ui/experiments/ui.dart
 FILE: ../../../flutter/lib/ui/floating_point.h
 FILE: ../../../flutter/lib/ui/geometry.dart
-FILE: ../../../flutter/lib/ui/hash_codes.dart
 FILE: ../../../flutter/lib/ui/hooks.dart
 FILE: ../../../flutter/lib/ui/io_manager.cc
 FILE: ../../../flutter/lib/ui/io_manager.h
@@ -45747,7 +45744,6 @@ 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/ui/dart_ui.gni

@@ -7,7 +7,6 @@ dart_ui_files = [
   "//flutter/lib/ui/channel_buffers.dart",
   "//flutter/lib/ui/compositing.dart",
   "//flutter/lib/ui/geometry.dart",
-  "//flutter/lib/ui/hash_codes.dart",
   "//flutter/lib/ui/hooks.dart",
   "//flutter/lib/ui/isolate_name_server.dart",
   "//flutter/lib/ui/key.dart",

lib/ui/experiments/ui.dart

@@ -32,7 +32,6 @@ part '../annotations.dart';
 part '../channel_buffers.dart';
 part '../compositing.dart';
 part '../geometry.dart';
-part '../hash_codes.dart';
 part '../hooks.dart';
 part '../isolate_name_server.dart';
 part '../key.dart';

lib/ui/hash_codes.dart

@@ -32,7 +32,6 @@ part 'annotations.dart';
 part 'channel_buffers.dart';
 part 'compositing.dart';
 part 'geometry.dart';
-part 'hash_codes.dart';
 part 'hooks.dart';
 part 'isolate_name_server.dart';
 part 'key.dart';

lib/ui/ui.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';