Issue #13441: Enable the workaround for Solaris locale bug

Skip locales triggering the mbstowcs() bug. I collected the locale list thanks
my previous commit:

 * hu_HU (ISO8859-2): character U+30000020
 * de_AT (ISO8859-1): character U+30000076
 * cs_CZ (ISO8859-2): character U+30000020
 * sk_SK (ISO8859-2): character U+30000020
 * pl_PL (ISO8859-2): character U+30000020
 * fr_CA (ISO8859-1): character U+30000020

Lib/test/test__locale.py

@@ -48,7 +48,7 @@ if sys.platform == 'sunos5':
                       % (loc, encoding, type(err), err))
             else:
                 locales.append(loc)
-        #candidate_locales = locales
+        candidate_locales = locales
     finally:
         locale.setlocale(locale.LC_ALL, old_locale)