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

sdk/lib/_internal/pub_generated/test/snapshot/doesnt_load_irrelevant_transformers_test.dart

 // Copyright (c) 2014, 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 'package:path/path.dart' as p;
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../descriptor.dart' as d;
@@ skipping 12 matching lines @@
 """;
 
 main() {
   initConfig();
 
   // Regression test for issue 20917.
   integration("snapshots the transformed version of an executable", () {
     servePackages((builder) {
       builder.serveRepoPackage('barback');
 
-      builder.serve("foo", "1.2.3",
+      builder.serve(
+          "foo",
+          "1.2.3",
           contents: [
-        d.dir("bin", [
-          d.file("hello.dart", "void main() => print('hello!');")
-        ])
-      ]);
+              d.dir("bin", [d.file("hello.dart", "void main() => print('hello!');")])]);
     });
 
-    d.dir(appPath, [
-      d.pubspec({
+    d.dir(appPath, [d.pubspec({
         "name": "myapp",
         "dependencies": {
           "foo": "1.2.3",
           "barback": "any"
         },
         "transformers": ["myapp"]
       }),
-      d.dir("lib", [
-        d.file("transformer.dart", BROKEN_TRANSFORMER)
-      ])
-    ]).create();
+          d.dir("lib", [d.file("transformer.dart", BROKEN_TRANSFORMER)])]).create();
 
     pubGet(output: contains("Precompiled foo:hello."));
 
-    d.dir(p.join(appPath, '.pub', 'bin'), [
-      d.dir('foo', [d.matcherFile('hello.dart.snapshot', contains('hello!'))])
-    ]).validate();
+    d.dir(
+        p.join(appPath, '.pub', 'bin'),
+        [
+            d.dir(
+                'foo',
+                [d.matcherFile('hello.dart.snapshot', contains('hello!'))])]).validate();
 
     var process = pubRun(args: ['foo:hello']);
     process.stdout.expect("hello!");
     process.shouldExit();
   });
 }