TLSProxy::Proxy: Don't use ReuseAddr on Windows

On Windows, we sometimes see a behavior with SO_REUSEADDR where there
remains lingering listening sockets on the same address and port as a
newly created one.

An easy solution is not to use ReuseAddr on Windows.

Thanks Bernd Edlinger for the suggestion.

Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/5103)