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

sdk/lib/_internal/pub_generated/test/downgrade/unlock_if_necessary_test.dart

Index: sdk/lib/_internal/pub_generated/test/downgrade/unlock_if_necessary_test.dart
diff --git a/sdk/lib/_internal/pub/test/downgrade/unlock_if_necessary_test.dart b/sdk/lib/_internal/pub_generated/test/downgrade/unlock_if_necessary_test.dart
similarity index 69%
copy from sdk/lib/_internal/pub/test/downgrade/unlock_if_necessary_test.dart
copy to sdk/lib/_internal/pub_generated/test/downgrade/unlock_if_necessary_test.dart
index 8561bb484c2f91f4c3c67487c16d1d2dfbd5a4a4..6eab79a1b8114ee51da992bac9c36a59d3faf42e 100644
--- a/sdk/lib/_internal/pub/test/downgrade/unlock_if_necessary_test.dart
+++ b/sdk/lib/_internal/pub_generated/test/downgrade/unlock_if_necessary_test.dart
@@ -9,14 +9,19 @@ import '../test_pub.dart';
 
 main() {
   initConfig();
-  integration("downgrades one locked hosted package's dependencies if it's "
-      "necessary", () {
+  integration(
+      "downgrades one locked hosted package's dependencies if it's " "necessary",
+      () {
     servePackages((builder) {
-      builder.serve("foo", "2.0.0", deps: {"foo_dep": "any"});
+      builder.serve("foo", "2.0.0", deps: {
+        "foo_dep": "any"
+      });
       builder.serve("foo_dep", "2.0.0");
     });
 
-    d.appDir({"foo": "any"}).create();
+    d.appDir({
+      "foo": "any"
+    }).create();
 
     pubGet();
 
@@ -26,7 +31,9 @@ main() {
     }).validate();
 
     servePackages((builder) {
-      builder.serve("foo", "1.0.0", deps: {"foo_dep": "<2.0.0"});
+      builder.serve("foo", "1.0.0", deps: {
+        "foo_dep": "<2.0.0"
+      });
       builder.serve("foo_dep", "1.0.0");
     });