locale.c: Use wrap_wsetlocale on Windows

This was the final remaining use of plain setlocale() on Windows.  All
others have been converted to wrap_wsetlocale, introduced in
6c33203.

There is no issue with the input name in this instance, since it is NULL
and not a character string, but it occurred to me that the locale name
returned by the function could be problematic.  _wsetlocale() should be
safe in all cases.

Author: khwilliamson

locale.c

@@ -2665,7 +2665,7 @@ S_win32_setlocale(pTHX_ int category, const char* locale)
         PL_cur_LC_ALL = savepv(result);
     }
     else {
-        PL_cur_LC_ALL = savepv(setlocale(LC_ALL, NULL));
+        PL_cur_LC_ALL = savepv(wrap_wsetlocale(LC_ALL, NULL));
     }
 
 #  endif