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

sdk/lib/_internal/pub_generated/test/transformer/fails_to_load_an_unconfigurable_transformer_when_config_is_passed_test.dart

Index: sdk/lib/_internal/pub_generated/test/transformer/fails_to_load_an_unconfigurable_transformer_when_config_is_passed_test.dart
diff --git a/sdk/lib/_internal/pub/test/transformer/fails_to_load_a_transform_with_an_import_error_test.dart b/sdk/lib/_internal/pub_generated/test/transformer/fails_to_load_an_unconfigurable_transformer_when_config_is_passed_test.dart
similarity index 54%
copy from sdk/lib/_internal/pub/test/transformer/fails_to_load_a_transform_with_an_import_error_test.dart
copy to sdk/lib/_internal/pub_generated/test/transformer/fails_to_load_an_unconfigurable_transformer_when_config_is_passed_test.dart
index 73b1e06c47fc4a3925dd820fa47da3678656c459..7c20db7fd9bb2a887bc2a8f442b2f102eed96950 100644
--- a/sdk/lib/_internal/pub/test/transformer/fails_to_load_a_transform_with_an_import_error_test.dart
+++ b/sdk/lib/_internal/pub_generated/test/transformer/fails_to_load_an_unconfigurable_transformer_when_config_is_passed_test.dart
@@ -13,25 +13,27 @@ import '../serve/utils.dart';
 main() {
   initConfig();
 
-  // An import error will cause the isolate API to fail synchronously while
-  // loading the transformer.
   withBarbackVersions("any", () {
-    integration("fails to load a transform with an import error", () {
-      d.dir(appPath, [
-        d.pubspec({
+    integration(
+        "fails to load an unconfigurable transformer when config is " "passed",
+        () {
+      d.dir(appPath, [d.pubspec({
           "name": "myapp",
-          "transformers": ["myapp/src/transformer"]
+          "transformers": [{
+              "myapp/src/transformer": {
+                'foo': 'bar'
+              }
+            }]
         }),
-        d.dir("lib", [d.dir("src", [
-          d.file("transformer.dart", "import 'does/not/exist.dart';")
-        ])])
-      ]).create();
+            d.dir(
+                "lib",
+                [d.dir("src", [d.file("transformer.dart", REWRITE_TRANSFORMER)])])]).create();
 
       createLockFile('myapp', pkg: ['barback']);
+
       var pub = startPubServe();
-      pub.stderr.expect("Unhandled exception:");
       pub.stderr.expect(
-          startsWith("Uncaught Error: Load Error: Failure getting "));
+          startsWith('No transformers that accept configuration ' 'were defined in '));
       pub.shouldExit(1);
     });
   });