Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/transcript_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 version_test;
-
-import 'package:unittest/unittest.dart';
-import 'test_pub.dart';
-import '../lib/src/transcript.dart';
-
-main() {
-  initConfig();
-
-  test("discards from the middle once it reaches the maximum", () {
-    var transcript = new Transcript<String>(4);
-    forEachToString() {
-      var result = "";
-      transcript.forEach((entry) => result += entry, (n) => result += "[$n]");
-      return result;
-    }
-
-    expect(forEachToString(), equals(""));
-    transcript.add("a");
-    expect(forEachToString(), equals("a"));
-    transcript.add("b");
-    expect(forEachToString(), equals("ab"));
-    transcript.add("c");
-    expect(forEachToString(), equals("abc"));
-    transcript.add("d");
-    expect(forEachToString(), equals("abcd"));
-    transcript.add("e");
-    expect(forEachToString(), equals("ab[1]de"));
-    transcript.add("f");
-    expect(forEachToString(), equals("ab[2]ef"));
-  });
-
-  test("does not discard if it doesn't reach the maximum", () {
-    var transcript = new Transcript<String>(40);
-    forEachToString() {
-      var result = "";
-      transcript.forEach((entry) => result += entry, (n) => result += "[$n]");
-      return result;
-    }
-
-    expect(forEachToString(), equals(""));
-    transcript.add("a");
-    expect(forEachToString(), equals("a"));
-    transcript.add("b");
-    expect(forEachToString(), equals("ab"));
-    transcript.add("c");
-    expect(forEachToString(), equals("abc"));
-    transcript.add("d");
-    expect(forEachToString(), equals("abcd"));
-    transcript.add("e");
-    expect(forEachToString(), equals("abcde"));
-    transcript.add("f");
-    expect(forEachToString(), equals("abcdef"));
-  });
-
-}