[ruby/net-http] Enforce write timeout when body_stream is used

The existing implementation of `Net::HTTP#write_timeout` relies on
`Net::BefferedIO` to trigger the `Net::WriteTimeout` error. This commit
changes `send_request_with_body_stream` to remove the optimization that
was making `Net::HTTP#write_timeout` not work when `body_stream` is
used.

Open issue:
https://bugs.ruby-lang.org/issues/17933

a0fab1ab52

lib/net/http/generic_request.rb

@@ -202,9 +202,7 @@ class Net::HTTPGenericRequest
       IO.copy_stream(f, chunker)
       chunker.finish
     else
-      # copy_stream can sendfile() to sock.io unless we use SSL.
-      # If sock.io is an SSLSocket, copy_stream will hit SSL_write()
-      IO.copy_stream(f, sock.io)
+      IO.copy_stream(f, sock)
     end
   end