Revert "Use native async/await support in pub."

sdk/lib/_internal/pub_generated/test/upgrade/git/upgrade_to_nonexistent_pubspec_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library pub_tests;
 
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
   initConfig();
   integration("upgrades Git packages to a nonexistent pubspec", () {
     ensureGit();
 
-    var repo = d.git('foo.git', [
-      d.libDir('foo'),
-      d.libPubspec('foo', '1.0.0')
-    ]);
+    var repo =
+        d.git('foo.git', [d.libDir('foo'), d.libPubspec('foo', '1.0.0')]);
     repo.create();
 
-    d.appDir({"foo": {"git": "../foo.git"}}).create();
+    d.appDir({
+      "foo": {
+        "git": "../foo.git"
+      }
+    }).create();
 
     pubGet();
 
-    d.dir(packagesPath, [
-      d.dir('foo', [
-        d.file('foo.dart', 'main() => "foo";')
-      ])
-    ]).validate();
+    d.dir(
+        packagesPath,
+        [d.dir('foo', [d.file('foo.dart', 'main() => "foo";')])]).validate();
 
     repo.runGit(['rm', 'pubspec.yaml']);
     repo.runGit(['commit', '-m', 'delete']);
 
-    pubUpgrade(error: new RegExp(r'Could not find a file named "pubspec.yaml" '
-        r'in "[^\n]*"\.'));
+    pubUpgrade(
+        error: new RegExp(
+            r'Could not find a file named "pubspec.yaml" ' r'in "[^\n]*"\.'));
 
-    d.dir(packagesPath, [
-      d.dir('foo', [
-        d.file('foo.dart', 'main() => "foo";')
-      ])
-    ]).validate();
+    d.dir(
+        packagesPath,
+        [d.dir('foo', [d.file('foo.dart', 'main() => "foo";')])]).validate();
   });
 }