ws2_32: Implement SIO_BSP_HANDLE_SELECT.
My understanding is that, in the absence of layered service providers, SIO_BSP_HANDLE_SELECT should behave like SIO_BASE_HANDLE (this is relied upon by https://github.com/python-trio/trio). Should I add tests to verify this? If so, should they basically just be the same as the existing SIO_BASE_HANDLE tests?