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

sdk/lib/_internal/pub_generated/test/snapshot/doesnt_resnapshot_when_a_dependency_is_unchanged_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;
 import '../test_pub.dart';
 
 main() {
   initConfig();
-  integration("doesn't recreate a snapshot when no dependencies of a package "
-      "have changed", () {
+  integration(
+      "doesn't recreate a snapshot when no dependencies of a package " "have changed",
+      () {
     servePackages((builder) {
-      builder.serve("foo", "1.2.3", deps: {"bar": "any"}, contents: [
-        d.dir("bin", [d.file("hello.dart", "void main() => print('hello!');")])
-      ]);
+      builder.serve("foo", "1.2.3", deps: {
+        "bar": "any"
+      },
+          contents: [
+              d.dir("bin", [d.file("hello.dart", "void main() => print('hello!');")])]);
       builder.serve("bar", "1.2.3");
     });
 
-    d.appDir({"foo": "1.2.3"}).create();
+    d.appDir({
+      "foo": "1.2.3"
+    }).create();
 
     pubGet(output: contains("Precompiled foo:hello."));
 
     pubUpgrade(output: isNot(contains("Precompiled foo:hello.")));
 
-    d.dir(p.join(appPath, '.pub', 'bin'), [
-      d.file('sdk-version', '0.1.2+3\n'),
-      d.dir('foo', [d.matcherFile('hello.dart.snapshot', contains('hello!'))])
-    ]).validate();
+    d.dir(
+        p.join(appPath, '.pub', 'bin'),
+        [
+            d.file('sdk-version', '0.1.2+3\n'),
+            d.dir(
+                'foo',
+                [d.matcherFile('hello.dart.snapshot', contains('hello!'))])]).validate();
   });
 }