Store the async-await compiled pub code directly in the repo.

sdk/lib/_internal/pub_generated/test/run/runs_transformer_in_entrypoint_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.
-
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import '../serve/utils.dart';
-
 const SCRIPT = """
 const TOKEN = "hi";
 main() {
   print(TOKEN);
 }
 """;
-
 main() {
   initConfig();
   withBarbackVersions("any", () {
     integration('runs transformers in the entrypoint package', () {
-      d.dir(appPath, [
-        d.pubspec({
+      d.dir(appPath, [d.pubspec({
           "name": "myapp",
           "transformers": ["myapp/src/transformer"]
         }),
-        d.dir("lib", [d.dir("src", [
-          d.file("transformer.dart", dartTransformer("transformed"))
-        ])]),
-        d.dir("bin", [
-          d.file("hi.dart", SCRIPT)
-        ])
-      ]).create();
-
+            d.dir(
+                "lib",
+                [d.dir("src", [d.file("transformer.dart", dartTransformer("transformed"))])]),
+            d.dir("bin", [d.file("hi.dart", SCRIPT)])]).create();
       createLockFile('myapp', pkg: ['barback']);
-
       var pub = pubRun(args: ["hi"]);
-
       pub.stdout.expect("(hi, transformed)");
       pub.shouldExit();
     });
   });
 }