Clean App.framework, Generated.xcconfig, flutter_export_environment.sh (#51532)

packages/flutter_tools/lib/src/ios/mac.dart

diff --git a/packages/flutter_tools/lib/src/ios/mac.dart b/packages/flutter_tools/lib/src/ios/mac.dart
index 6e4971a..e6b3060 100644
--- a/packages/flutter_tools/lib/src/ios/mac.dart
+++ b/packages/flutter_tools/lib/src/ios/mac.dart
@@ -429,16 +429,6 @@
     result.stdout.contains('there are two concurrent builds running');
 }
 
-String readGeneratedXcconfig(String appPath) {
-  final String generatedXcconfigPath =
-      globals.fs.path.join(globals.fs.currentDirectory.path, appPath, 'Flutter', 'Generated.xcconfig');
-  final File generatedXcconfigFile = globals.fs.file(generatedXcconfigPath);
-  if (!generatedXcconfigFile.existsSync()) {
-    return null;
-  }
-  return generatedXcconfigFile.readAsStringSync();
-}
-
 Future<void> diagnoseXcodeBuildFailure(XcodeBuildResult result) async {
   if (result.xcodeBuildExecution != null &&
       result.xcodeBuildExecution.buildForPhysicalDevice &&

packages/flutter_tools/lib/src/ios/xcodeproj.dart

diff --git a/packages/flutter_tools/lib/src/ios/xcodeproj.dart b/packages/flutter_tools/lib/src/ios/xcodeproj.dart
index d415c39..108436a 100644
--- a/packages/flutter_tools/lib/src/ios/xcodeproj.dart
+++ b/packages/flutter_tools/lib/src/ios/xcodeproj.dart
@@ -357,8 +357,8 @@
     }
   }
 
-  void cleanWorkspace(String workspacePath, String scheme) {
-    _processUtils.runSync(<String>[
+  Future<void> cleanWorkspace(String workspacePath, String scheme) async {
+    await _processUtils.run(<String>[
       _executable,
       '-workspace',
       workspacePath,