* Revert "Add logging if FlutterDartProject fails to load the application kernel snapshot (#6257)"
This reverts commit d29c7db769d1a0d45f579b76ee3a43f38dc7318d.
* Revert "Update deprecated subtags from language subtag registry. (#6280)"
This reverts commit 2a1debfccfe2cc00e596607ac7cb1d29d2af8834.
* Revert "Add Xib splashscreen support (#6289)"
This reverts commit 540cd96262ed87bb6cd26ac18ad5468e70c3af63.
* Revert "Fix a compilation problem when using iPhoneOS12.0sdk(Xcode10) && clang version 7.0.0. (#6279)"
This reverts commit 05f21e63a115db2db161c8265be8e8349f3d7df0.