Issue #20076: Apply optimization in makelocalealias.py repeatedly.

Remove just added the sr_rs.utf8@latn alias because it is
derived from sr_rs@latin.

Lib/locale.py

@@ -1264,7 +1264,6 @@ locale_alias = {
     'sr_cs@latn':                           'sr_CS.UTF-8@latin',
     'sr_me':                                'sr_ME.UTF-8',
     'sr_rs':                                'sr_RS.UTF-8',
-    'sr_rs.utf8@latn':                      'sr_RS.UTF-8@latin',
     'sr_rs@latn':                           'sr_RS.UTF-8@latin',
     'sr_sp':                                'sr_CS.ISO8859-2',
     'sr_yu':                                'sr_RS.UTF-8@latin',

Tools/i18n/makelocalealias.py

@@ -133,7 +133,12 @@ if __name__ == '__main__':
     if args.glibc_supported:
         data.update(parse_glibc_supported(args.glibc_supported))
     data.update(parse(args.locale_alias))
-    data = optimize(data)
+    while True:
+        # Repeat optimization while the size is decreased.
+        n = len(data)
+        data = optimize(data)
+        if len(data) == n:
+            break
     print_differences(data, locale.locale_alias)
     print()
     print('locale_alias = {')