This reverts commit f755e8a8. That
change meant our EditorFeatures code was using DllImports in the
cross-platform binary, and we weren't sure what that would do in
VS for Mac if that code ran. It also brought a dependency on
Microsoft.VisualStudio.RemoteControl, which also seems to depend on
various Windows specific APIs.

We'll finish up the decision of what to do in
https://github.com/dotnet/roslyn/pull/45115