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

sdk/lib/_internal/pub_generated/test/serve/serve_from_app_lib_test.dart

Index: sdk/lib/_internal/pub_generated/test/serve/serve_from_app_lib_test.dart
diff --git a/sdk/lib/_internal/pub/test/serve/serve_from_app_lib_test.dart b/sdk/lib/_internal/pub_generated/test/serve/serve_from_app_lib_test.dart
similarity index 74%
copy from sdk/lib/_internal/pub/test/serve/serve_from_app_lib_test.dart
copy to sdk/lib/_internal/pub_generated/test/serve/serve_from_app_lib_test.dart
index ad4e91ad72d32c2dfd86d3fe45b9c96986e730d4..2204ff640cfa772ac336b7cbe11814a6a40b7de7 100644
--- a/sdk/lib/_internal/pub/test/serve/serve_from_app_lib_test.dart
+++ b/sdk/lib/_internal/pub_generated/test/serve/serve_from_app_lib_test.dart
@@ -11,15 +11,15 @@ import 'utils.dart';
 main() {
   initConfig();
   integration("'packages' URLs look in the app's lib directory", () {
-    d.dir(appPath, [
-      d.appPubspec(),
-      d.dir("lib", [
-        d.file("lib.dart", "foo() => 'foo';"),
-        d.dir("sub", [
-          d.file("lib.dart", "bar() => 'bar';"),
-        ])
-      ])
-    ]).create();
+    d.dir(
+        appPath,
+        [
+            d.appPubspec(),
+            d.dir(
+                "lib",
+                [
+                    d.file("lib.dart", "foo() => 'foo';"),
+                    d.dir("sub", [d.file("lib.dart", "bar() => 'bar';"),])])]).create();
 
     pubServe();
     requestShouldSucceed("packages/myapp/lib.dart", "foo() => 'foo';");