kernel32.dll EntryPoint "CopyMemory" should be "RtlMoveMemory" on .NET 9

[Nytra]

[DllImport("kernel32.dll", EntryPoint = "CopyMemory", SetLastError = false)]

This prevented me from using CircularBuffer on .NET 9 until I fixed it. I'm not sure if changing it will break older .NET versions though.

More info: dotnet/wpf#586