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

sdk/lib/_internal/pub_generated/test/get/path/nonexistent_dir_test.dart

Index: sdk/lib/_internal/pub_generated/test/get/path/nonexistent_dir_test.dart
diff --git a/sdk/lib/_internal/pub/test/get/path/nonexistent_dir_test.dart b/sdk/lib/_internal/pub_generated/test/get/path/nonexistent_dir_test.dart
similarity index 78%
copy from sdk/lib/_internal/pub/test/get/path/nonexistent_dir_test.dart
copy to sdk/lib/_internal/pub_generated/test/get/path/nonexistent_dir_test.dart
index 6a983c4cca3d4566d1dfbfdb62aa55614332f605..8496cba3399a6ce8df9036b56ec21a7f10d0c586 100644
--- a/sdk/lib/_internal/pub/test/get/path/nonexistent_dir_test.dart
+++ b/sdk/lib/_internal/pub_generated/test/get/path/nonexistent_dir_test.dart
@@ -13,16 +13,15 @@ main() {
   integration('path dependency to non-existent directory', () {
     var badPath = path.join(sandboxDir, "bad_path");
 
-    d.dir(appPath, [
-      d.appPubspec({
-        "foo": {"path": badPath}
-      })
-    ]).create();
+    d.dir(appPath, [d.appPubspec({
+        "foo": {
+          "path": badPath
+        }
+      })]).create();
 
     pubGet(error: """
         Could not find package foo at "$badPath".
         Depended on by:
-        - myapp 0.0.0""",
-        exitCode: exit_codes.UNAVAILABLE);
+        - myapp 0.0.0""", exitCode: exit_codes.UNAVAILABLE);
   });
-}
+}