C locale has no CurrentCulture.Name but creates a en_US_POSIX collation locale so modify the nonexistent fallback test
C locale has no CurrentCulture.Name but creates a en_US_POSIX collation locale
so modify the nonexistent fallback test

conniey/icu-dotnet,ermshiperete/icu-dotnet,conniey/icu-dotnet,sillsdev/icu-dotnet,sillsdev/icu-dotnet,ermshiperete/icu-dotnet