Bug 1818441 - Make intl/locale/tests/gtest buildable outside of a unified build environment r=andi

Depends on D170723

Differential Revision: https://phabricator.services.mozilla.com/D170724

intl/locale/tests/gtest/TestOSPreferences.cpp

@@ -7,6 +7,7 @@
 #include "mozilla/ArrayUtils.h"
 #include "mozilla/gtest/MozAssertions.h"
 #include "mozilla/Preferences.h"
+#include "mozilla/intl/LocaleService.h"
 #include "mozilla/intl/OSPreferences.h"
 
 using namespace mozilla::intl;

intl/locale/tests/gtest/moz.build

@@ -12,5 +12,3 @@ UNIFIED_SOURCES += [
 ]
 
 FINAL_LIBRARY = "xul-gtest"
-
-REQUIRES_UNIFIED_BUILD = True