Try fixing web tool tests on windows (#78386)

dev/try_builders.json

@@ -754,7 +754,8 @@
       "name": "Windows web_tool_tests",
       "repo": "flutter",
       "task_name": "win_web_tool_tests",
-      "enabled": false
+      "enabled": true,
+      "run_if": ["dev/**", "packages/flutter_tools/**", "bin/**"]
     }
   ]
 }

packages/flutter_tools/lib/src/isolated/devfs_web.dart

@@ -452,7 +452,8 @@ class WebAssetServer implements AssetReader {
   }
 
   /// Tear down the http server running.
-  Future<void> dispose() {
+  Future<void> dispose() async {
+    await dwds?.stop();
     return _httpServer.close();
   }
 

packages/flutter_tools/lib/src/web/chrome.dart

@@ -173,7 +173,8 @@ class ChromiumLauncher {
 
     final String chromeExecutable = _browserFinder(_platform, _fileSystem);
 
-    if (_logger.isVerbose) {
+    if (_logger.isVerbose && !_platform.isWindows) {
+      // Note: --version is not supported on windows.
       final ProcessResult versionResult = await _processManager.run(<String>[chromeExecutable, '--version']);
       _logger.printTrace('Using ${versionResult.stdout}');
     }

packages/flutter_tools/test/web.shard/debugger_stepping_web_test.dart

@@ -4,6 +4,7 @@
 
 // @dart = 2.8
 
+@Timeout(Duration(minutes: 3))
 import 'package:file/file.dart';
 
 import '../integration.shard/test_data/stepping_project.dart';
@@ -48,7 +49,7 @@ void main() {
         reason: 'After $i steps, debugger should stop at $expectedLine but stopped at $actualLine'
       );
     }
-  }, skip: platform.isWindows); // https://github.com/flutter/flutter/issues/70486
+  });
 
   tearDown(() async {
     await flutter.stop();

packages/flutter_tools/test/web.shard/expression_evaluation_web_test.dart

@@ -4,6 +4,7 @@
 
 // @dart = 2.8
 
+@Timeout(Duration(minutes: 3))
 import 'package:file/file.dart';
 import 'package:matcher/matcher.dart';
 import 'package:vm_service/vm_service.dart';
@@ -168,7 +169,7 @@ void batch2() {
     await breakInMethod(_flutter);
     await evaluateComplexExpressions(_flutter);
     await cleanProject();
-  }, skip: 'https://github.com/dart-lang/sdk/issues/41480');
+  });
 }
 
 Future<void> failToEvaluateExpression(FlutterTestDriver flutter) async {

packages/flutter_tools/test/web.shard/hot_reload_web_test.dart

@@ -4,6 +4,7 @@
 
 // @dart = 2.8
 
+@Timeout(Duration(minutes: 3))
 import 'dart:async';
 
 import 'package:file/file.dart';

packages/flutter_tools/test/web.shard/web_run_test.dart

@@ -4,6 +4,7 @@
 
 // @dart = 2.8
 
+@Timeout(Duration(minutes: 3))
 import 'package:file/file.dart';
 import 'package:flutter_tools/src/base/file_system.dart';