stream_put uses inconsistent stream_id

[Mellich]

stream_put requires to pass a stream_id. This stream_id needs to be >= 9. In the C++ driver, this id is subtracted by 9 in this line because of non-obvious reasons.

This leads to the issue, that if stream_put is called with stream_id=9 and source and destination rank are the same, it will send the data to stream_id=0.
The behavior is described in this test which should pass in my eyes.

For send/recv, the stream_id/tag is used as expected as it can be seen in this test.

In my opinion, the behavior should be the same for both operations.

[Mellich]

Resolved in #111.