Avoid creating zh-CHS/zh-CHT durng culture enumeration

Avoid creating zh-CHS/zh-CHT durng culture enumeration

zh-CHS and zh-CHT are old names that is not really supported in the standards.
when we enabled CultureInfo.GetCultures() there was some code that create cultures
for zh-CHS and zh-CHT. The fix here is disable that otherwise we'll have to enable
a good chunk of legacy code to support it while it never supported by coreclr and in
same time are not names used in standards

Commit migrated from https://github.com/dotnet/coreclr/commit/7ac54bcc7fc17792e283da809e72b44ae8da02a4