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

sdk/lib/_internal/pub_generated/test/build/outputs_error_to_json_test.dart

Index: sdk/lib/_internal/pub_generated/test/build/outputs_error_to_json_test.dart
diff --git a/sdk/lib/_internal/pub/test/build/outputs_error_to_json_test.dart b/sdk/lib/_internal/pub_generated/test/build/outputs_error_to_json_test.dart
similarity index 64%
copy from sdk/lib/_internal/pub/test/build/outputs_error_to_json_test.dart
copy to sdk/lib/_internal/pub_generated/test/build/outputs_error_to_json_test.dart
index bbd31fdddcd2c787d3d08791ac4e2b4d8aadfc85..38f42bdba04e9476594af0dd08e7ff90a18b2b5a 100644
--- a/sdk/lib/_internal/pub/test/build/outputs_error_to_json_test.dart
+++ b/sdk/lib/_internal/pub_generated/test/build/outputs_error_to_json_test.dart
@@ -32,33 +32,23 @@ main() {
       // timeout.
       currentSchedule.timeout *= 2;
 
-      d.dir(appPath, [
-        d.pubspec({
+      d.dir(appPath, [d.pubspec({
           "name": "myapp",
           "transformers": ["myapp"]
         }),
-        d.dir("lib", [
-          d.file("transformer.dart", TRANSFORMER)
-        ]),
-        d.dir("web", [
-          d.file("foo.txt", "foo")
-        ])
-      ]).create();
+            d.dir("lib", [d.file("transformer.dart", TRANSFORMER)]),
+            d.dir("web", [d.file("foo.txt", "foo")])]).create();
 
       createLockFile('myapp', pkg: ['barback']);
 
-      schedulePub(args: ["build", "--format", "json"],
-          outputJson: {
-            "buildResult": "failure",
-            "errors": [
-              {
-                "error": startsWith("Transform Rewrite on myapp|web/foo.txt "
-                    "threw error: oh no!")
-              }
-            ],
-            "log": []
-          },
-          exitCode: exit_codes.DATA);
+      schedulePub(args: ["build", "--format", "json"], outputJson: {
+        "buildResult": "failure",
+        "errors": [{
+            "error": startsWith(
+                "Transform Rewrite on myapp|web/foo.txt " "threw error: oh no!")
+          }],
+        "log": []
+      }, exitCode: exit_codes.DATA);
     });
   });
 }