As described in https://github.com/electron/electron/pull/13769, we had to disable mixed sandbox related tests for Windows CI. We should re-enable them back after finding out the root reason.
atom/app/atom_main_delegate.cc
std::string custom_locale;
  ui::ResourceBundle::InitSharedInstanceWithLocale(
      custom_locale, nullptr, ui::ResourceBundle::LOAD_COMMON_RESOURCES);
  auto* cmd_line = base::CommandLine::ForCurrentProcess();
  if (cmd_line->HasSwitch(::switches::kLang)) {
    const std::string locale = cmd_line->GetSwitchValueASCII(::switches::kLang);
    const base::FilePath locale_file_path =
        ui::ResourceBundle::GetSharedInstance().GetLocaleFilePath(locale, true);
    if (!locale_file_path.empty()) {
      custom_locale = locale;
#if defined(OS_LINUX)
      /* When built with USE_GLIB, libcc's GetApplicationLocaleInternal() uses
       * glib's g_get_language_names(), which keys off of getenv("LC_ALL") */
      g_setenv("LC_ALL", custom_locale.c_str(), TRUE);
#endif
    }
  }
#if defined(OS_MACOSX)
  if (custom_locale.empty())
    l10n_util::OverrideLocaleWithCocoaLocale();
#endif
  LoadResourceBundle(custom_locale);
  AtomBrowserClient::SetApplicationLocale(
      l10n_util::GetApplicationLocale(custom_locale));
}
void AtomMainDelegate::PreSandboxStartup() {