* Revert "Include a directory with Flutter assets (#12944)" This reverts commit3af6b9cbf5. * Revert "Upgrade project.pbxproj to include flutter_assets (#13011)" This reverts commit08128cb29b. * Revert "Upgrade complex_layout project.pbxproj to include flutter_assets (#13544)" This reverts commit35f1a04195. * mark complex_layout_ios__start_up as flaky