stream: Improve half-closing of outgoing TCP connections (#28624)

Notably fixes the case where upstream finished before the connection
was successfully established, and avoids RSTing the incoming stream
when the outgoing stream is done (which is now possible due to the
cancellation reason being propagated).

akka-actor/src/main/scala/akka/io/TcpConnection.scala

@@ -142,6 +142,7 @@ private[io] abstract class TcpConnection(val tcp: TcpExt, val channel: SocketCha
     case SuspendReading  => suspendReading(info)
     case ResumeReading   => resumeReading(info)
     case ChannelReadable => doRead(info, closeCommander)
+    case Close           => doCloseConnection(info.handler, closeCommander, Close.event)
     case Abort           => handleClose(info, Some(sender()), Aborted)
   }