RubyIO#select puts connectable sockets in the read set instead of write set

Perusing RubyIO.select_static(), it puts sockets that have OP_CONNECT set in their SelectionKey#readyOps() flags into the read set instead of the write set as one would expect.

This is probably not a user-visible bug, since OP_CONNECT is never registered in the interest ops for any write channels, so it should never be set in the ready ops.

Technically OP_CONNECT probably should be set in the interest ops for IO objects in the write set, but since any socket that connects is also writable, it works as it is anyway.

Just documenting for future reference.