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

sdk/lib/_internal/pub_generated/test/snapshot/prints_errors_for_broken_snapshots_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("prints errors for broken snapshot compilation", () {
-    servePackages((builder) {
-      builder.serve(
-          "foo",
-          "1.2.3",
-          contents: [
-              d.dir(
-                  "bin",
-                  [
-                      d.file("hello.dart", "void main() { no closing brace"),
-                      d.file("goodbye.dart", "void main() { no closing brace"),])]);
-      builder.serve(
-          "bar",
-          "1.2.3",
-          contents: [
-              d.dir(
-                  "bin",
-                  [
-                      d.file("hello.dart", "void main() { no closing brace"),
-                      d.file("goodbye.dart", "void main() { no closing brace"),])]);
-    });
-
-    d.appDir({
-      "foo": "1.2.3",
-      "bar": "1.2.3"
-    }).create();
-
-    // This should still have a 0 exit code, since installation succeeded even
-    // if precompilation didn't.
-    pubGet(
-        error: allOf(
-            [
-                contains("Failed to precompile foo:hello"),
-                contains("Failed to precompile foo:goodbye"),
-                contains("Failed to precompile bar:hello"),
-                contains("Failed to precompile bar:goodbye")]),
-        exitCode: 0);
-
-    d.dir(
-        p.join(appPath, '.pub', 'bin'),
-        [
-            d.file('sdk-version', '0.1.2+3\n'),
-            d.dir(
-                'foo',
-                [d.nothing('hello.dart.snapshot'), d.nothing('goodbye.dart.snapshot')]),
-            d.dir(
-                'bar',
-                [
-                    d.nothing('hello.dart.snapshot'),
-                    d.nothing('goodbye.dart.snapshot')])]).validate();
-  });
-}