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

sdk/lib/_internal/pub_generated/test/get/dry_run_does_not_apply_changes_test.dart

Index: sdk/lib/_internal/pub_generated/test/get/dry_run_does_not_apply_changes_test.dart
diff --git a/sdk/lib/_internal/pub/test/get/dry_run_does_not_apply_changes_test.dart b/sdk/lib/_internal/pub_generated/test/get/dry_run_does_not_apply_changes_test.dart
similarity index 65%
copy from sdk/lib/_internal/pub/test/get/dry_run_does_not_apply_changes_test.dart
copy to sdk/lib/_internal/pub_generated/test/get/dry_run_does_not_apply_changes_test.dart
index 7a07d25a6d71a1b9767a76b07f7f02855ef9a5cb..a23d6bdcd08159a149d1919e5c66a3bd92af4d5b 100644
--- a/sdk/lib/_internal/pub/test/get/dry_run_does_not_apply_changes_test.dart
+++ b/sdk/lib/_internal/pub_generated/test/get/dry_run_does_not_apply_changes_test.dart
@@ -18,16 +18,14 @@ main() {
       "foo": "1.0.0"
     }).create();
 
-    pubGet(args: ["--dry-run"], output: allOf([
-      contains("+ foo 1.0.0"),
-      contains("Would change 1 dependency.")
-    ]));
+    pubGet(
+        args: ["--dry-run"],
+        output: allOf(
+            [contains("+ foo 1.0.0"), contains("Would change 1 dependency.")]));
 
-    d.dir(appPath, [
-      // The lockfile should not be created.
+    d.dir(appPath, [// The lockfile should not be created.
       d.nothing("pubspec.lock"),
-      // The "packages" directory should not have been generated.
-      d.nothing("packages")
-    ]).validate();
+          // The "packages" directory should not have been generated.
+      d.nothing("packages")]).validate();
   });
 }