QLocale: Use QVariant::toStringList() instead of template instantiation

Avoids (binary) code duplication.

Change-Id: I57a23e2f6e151963163d8073b309b3562f8e8684
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/tools/qlocale_unix.cpp

@@ -247,7 +247,7 @@ QVariant QSystemLocale::query(QueryType type, QVariant in) const
     case StringToAlternateQuotation:
         return lc_messages.quoteString(in.value<QStringRef>(), QLocale::AlternateQuotation);
     case ListToSeparatedString:
-        return lc_messages.createSeparatedList(in.value<QStringList>());
+        return lc_messages.createSeparatedList(in.toStringList());
     case LocaleChanged:
         Q_ASSERT(false);
     default: