MEDIUM: mux-quic/h3/qpack: use ncbuf for uni streams

This commit is the equivalent for uni-streams of previous commit
  MEDIUM: mux-quic/h3/hq-interop: use ncbuf for bidir streams

All unidirectional streams data is now handle in MUX Rx ncbuf. The
obsolete buffer is not unused and will be cleared in the following
patches.
3 files changed