MEDIUM: mux-h1: Properly handle tunnel establishments and aborts

MEDIUM: mux-h1: Properly handle tunnel establishments and aborts

In the same way than the H2 mux, we now bloc data sending on the server side
if a tunnel is not fully established. In addition, if some data are still
pending for a aborted tunnel, an error is triggered and the server
connection is closed.

To do so, we rely on the H1C_F_WAIT_INPUT flag to bloc the output
processing. This patch contributes to fix the tunnel mode between the H1 and
the H2 muxes.