Fix gradle_plugin_light_apk test. (#66496)

dev/devicelab/lib/framework/apk_utils.dart

@@ -8,6 +8,9 @@ import 'package:path/path.dart' as path;
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/utils.dart';
 
+
+final String platformLineSep = Platform.isWindows ? '\r\n' : '\n';
+
 final List<String> flutterAssets = <String>[
   'assets/flutter_assets/AssetManifest.json',
   'assets/flutter_assets/NOTICES',
@@ -267,8 +270,8 @@ subprojects {
     final File pubspec = File(path.join(rootPath, 'pubspec.yaml'));
     String content = await pubspec.readAsString();
     content = content.replaceFirst(
-      '\ndependencies:\n',
-      '\ndependencies:\n  $plugin:\n',
+      '${platformLineSep}dependencies:$platformLineSep',
+      '${platformLineSep}dependencies:$platformLineSep  $plugin:$platformLineSep',
     );
     await pubspec.writeAsString(content, flush: true);
   }
@@ -315,7 +318,7 @@ android {
       path.join(parent.path, 'hello', 'pubspec.yaml')
     );
     final String contents = pubspec.readAsStringSync();
-    final String newContents = contents.replaceFirst('# The following section is specific to Flutter.\nflutter:\n', '''
+    final String newContents = contents.replaceFirst('# The following section is specific to Flutter.${platformLineSep}flutter:$platformLineSep', '''
 flutter:
   assets:
     - lib/gallery/example_code.dart

dev/try_builders.json

@@ -357,6 +357,13 @@
          "enabled":true,
          "run_if":["dev/**", "bin/**"]
       },
+      {
+         "name": "Windows gradle_plugin_light_apk_test",
+         "repo": "flutter",
+         "task_name": "win_gradle_plugin_light_apk_test",
+         "enabled":true,
+         "run_if":["dev/**", "bin/**"]
+      },
       {
          "name": "Windows gradle_r8_test",
          "repo": "flutter",