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

sdk/lib/_internal/pub_generated/test/barback/directory_args_test.dart

+import 'package:scheduled_test/scheduled_test.dart';
+import '../descriptor.dart' as d;
+import '../test_pub.dart';
+import '../serve/utils.dart';
+main() {
+  initConfig();
+  setUp(() {
+    d.dir(
+        appPath,
+        [
+            d.appPubspec(),
+            d.dir('bar', [d.file('file.txt', 'bar')]),
+            d.dir('foo', [d.file('file.txt', 'foo')]),
+            d.dir('test', [d.file('file.txt', 'test')]),
+            d.dir('web', [d.file('file.txt', 'web')])]).create();
+  });
+  integration("builds only the given directories", () {
+    schedulePub(
+        args: ["build", "foo", "bar"],
+        output: new RegExp(r'Built 2 files to "build".'));
+    d.dir(
+        appPath,
+        [
+            d.dir(
+                'build',
+                [
+                    d.dir('bar', [d.file('file.txt', 'bar')]),
+                    d.dir('foo', [d.file('file.txt', 'foo')]),
+                    d.nothing('test'),
+                    d.nothing('web')])]).validate();
+  });
+  integration("serves only the given directories", () {
+    pubServe(args: ["foo", "bar"]);
+    requestShouldSucceed("file.txt", "bar", root: "bar");
+    requestShouldSucceed("file.txt", "foo", root: "foo");
+    expectNotServed("test");
+    expectNotServed("web");
+    endPubServe();
+  });
+}