[flutter_tools] remove workaround for caching sound dill (#70014)

diff --git a/packages/flutter_tools/lib/src/bundle.dart b/packages/flutter_tools/lib/src/bundle.dart
index be1e3b7..f200ab6 100644
--- a/packages/flutter_tools/lib/src/bundle.dart
+++ b/packages/flutter_tools/lib/src/bundle.dart
@@ -29,12 +29,10 @@
 
 String getDefaultApplicationKernelPath({
   @required bool trackWidgetCreation,
-  @required NullSafetyMode nullSafetyMode,
 }) {
   return getKernelPathForTransformerOptions(
     globals.fs.path.join(getBuildDirectory(), 'app.dill'),
     trackWidgetCreation: trackWidgetCreation,
-    nullSafetyMode: nullSafetyMode,
   );
 }
 
@@ -42,7 +40,6 @@
   @required bool trackWidgetCreation,
   @required List<String> dartDefines,
   @required List<String> extraFrontEndOptions,
-  @required NullSafetyMode nullSafetyMode,
 }) {
   final StringBuffer buffer = StringBuffer();
   buffer.writeAll(dartDefines);
@@ -56,21 +53,13 @@
   return getKernelPathForTransformerOptions(
     globals.fs.path.join(getBuildDirectory(), '${buildPrefix}cache.dill'),
     trackWidgetCreation: trackWidgetCreation,
-    nullSafetyMode: nullSafetyMode,
   );
 }
 
 String getKernelPathForTransformerOptions(
   String path, {
   @required bool trackWidgetCreation,
-  @required NullSafetyMode nullSafetyMode,
 }) {
-  // Temporary work around until --initialize-from-dill accounts for sound mode.
-  // The tool does not know the compilation mode if [NullSafetyMode.autodetect] is
-  // selected.
-  if (nullSafetyMode == NullSafetyMode.sound) {
-    path += '.sound';
-  }
   if (trackWidgetCreation) {
     path += '.track.dill';
   }
diff --git a/packages/flutter_tools/lib/src/resident_runner.dart b/packages/flutter_tools/lib/src/resident_runner.dart
index e01c04d..ab841cc 100644
--- a/packages/flutter_tools/lib/src/resident_runner.dart
+++ b/packages/flutter_tools/lib/src/resident_runner.dart
@@ -123,7 +123,6 @@
           trackWidgetCreation: buildInfo.trackWidgetCreation,
           dartDefines: buildInfo.dartDefines,
           extraFrontEndOptions: extraFrontEndOptions,
-          nullSafetyMode: buildInfo.nullSafetyMode,
         ),
         targetModel: TargetModel.dartdevc,
         extraFrontEndOptions: extraFrontEndOptions,
@@ -165,7 +164,6 @@
           trackWidgetCreation: buildInfo.trackWidgetCreation,
           dartDefines: buildInfo.dartDefines,
           extraFrontEndOptions: extraFrontEndOptions,
-          nullSafetyMode: buildInfo.nullSafetyMode,
         ),
         packagesPath: buildInfo.packagesPath,
         artifacts: globals.artifacts,
@@ -1181,7 +1179,6 @@
         trackWidgetCreation: trackWidgetCreation,
         dartDefines: debuggingOptions.buildInfo.dartDefines,
         extraFrontEndOptions: debuggingOptions.buildInfo.extraFrontEndOptions,
-        nullSafetyMode: debuggingOptions.buildInfo.nullSafetyMode,
       );
       globals.fs
           .file(copyPath)
diff --git a/packages/flutter_tools/lib/src/run_hot.dart b/packages/flutter_tools/lib/src/run_hot.dart
index ca77c8d..e7feae5 100644
--- a/packages/flutter_tools/lib/src/run_hot.dart
+++ b/packages/flutter_tools/lib/src/run_hot.dart
@@ -330,7 +330,6 @@
             outputPath: dillOutputPath ??
               getDefaultApplicationKernelPath(
                 trackWidgetCreation: debuggingOptions.buildInfo.trackWidgetCreation,
-                nullSafetyMode: debuggingOptions.buildInfo.nullSafetyMode,
               ),
             packageConfig: packageConfig,
           ).then((CompilerOutput output) => output?.errorCount == 0)
diff --git a/packages/flutter_tools/lib/src/test/test_compiler.dart b/packages/flutter_tools/lib/src/test/test_compiler.dart
index 907f9a4..5ccce38 100644
--- a/packages/flutter_tools/lib/src/test/test_compiler.dart
+++ b/packages/flutter_tools/lib/src/test/test_compiler.dart
@@ -45,7 +45,6 @@
         'test_cache',
         getDefaultCachedKernelPath(
           trackWidgetCreation: buildInfo.trackWidgetCreation,
-          nullSafetyMode: buildInfo.nullSafetyMode,
           dartDefines: buildInfo.dartDefines,
           extraFrontEndOptions: buildInfo.extraFrontEndOptions,
         )) {
diff --git a/packages/flutter_tools/lib/src/tester/flutter_tester.dart b/packages/flutter_tools/lib/src/tester/flutter_tester.dart
index d758b2b..974d4c1 100644
--- a/packages/flutter_tools/lib/src/tester/flutter_tester.dart
+++ b/packages/flutter_tools/lib/src/tester/flutter_tester.dart
@@ -153,7 +153,6 @@
     final String applicationKernelFilePath = getKernelPathForTransformerOptions(
       _fileSystem.path.join(_buildDirectory, 'flutter-tester-app.dill'),
       trackWidgetCreation: buildInfo.trackWidgetCreation,
-      nullSafetyMode: buildInfo.nullSafetyMode,
     );
     // Build assets and perform initial compilation.
     await BundleBuilder().build(
diff --git a/packages/flutter_tools/test/general.shard/resident_runner_test.dart b/packages/flutter_tools/test/general.shard/resident_runner_test.dart
index 824387e..25e8aba 100644
--- a/packages/flutter_tools/test/general.shard/resident_runner_test.dart
+++ b/packages/flutter_tools/test/general.shard/resident_runner_test.dart
@@ -2397,40 +2397,6 @@
     expect(await globals.fs.file(globals.fs.path.join('build', 'cache.dill.track.dill')).readAsString(), 'ABC');
   }));
 
-  testUsingContext('HotRunner copies compiled app.dill to cache during startup with --sound-null-safety', () => testbed.run(() async {
-    fakeVmServiceHost = FakeVmServiceHost(requests: <VmServiceExpectation>[
-      listViews,
-      listViews,
-      setAssetBundlePath,
-    ]);
-    setWsAddress(testUri, fakeVmServiceHost.vmService);
-    globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
-    residentRunner = HotRunner(
-      <FlutterDevice>[
-        mockFlutterDevice,
-      ],
-      stayResident: false,
-      debuggingOptions: DebuggingOptions.enabled(const BuildInfo(
-        BuildMode.debug,
-        '',
-        treeShakeIcons: false,
-        trackWidgetCreation: true,
-        nullSafetyMode: NullSafetyMode.sound,
-      )),
-    );
-    residentRunner.artifactDirectory.childFile('app.dill').writeAsStringSync('ABC');
-    when(mockFlutterDevice.runHot(
-      hotRunner: anyNamed('hotRunner'),
-      route: anyNamed('route'),
-    )).thenAnswer((Invocation invocation) async {
-      return 0;
-    });
-    await residentRunner.run();
-
-    expect(await globals.fs.file(globals.fs.path.join('build', 'cache.dill.sound.track.dill')).readAsString(), 'ABC');
-  }));
-
-
   testUsingContext('HotRunner unforwards device ports', () => testbed.run(() async {
     fakeVmServiceHost = FakeVmServiceHost(requests: <VmServiceExpectation>[
       listViews,