[Tracking] HashTable/ArrayList replacement in Winforms

While replacing HashSet and ArrayList we found scenarios where replacements from Generics are not functionally equivalent with non-generics. ex: [HashTable/ArrayLaist replacement in Winforms](https://github.com/dotnet/winforms/pull/8235/files#r1044787174).

We are going to do a quick review around [here](https://github.com/dotnet/winforms/issues/8140) and [here](https://github.com/dotnet/winforms/issues/8143) and provide further guidance/helpers to make sure replacements are smooth.

related #8143 , #8140

Community and primarily @elachlan , @Jericho , @hughbe @gpetrou that are helping in this space, can you help us on [these](https://github.com/dotnet/winforms/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22) meanwhile?