quiche: fix segfault and other things

quiche: fix segfault and other things

- refs #11449 where a segfault is reported when IP Eyeballing did
  not immediately connect but made several attempts
- The transfer initiating the eyeballing was initialized  too early,
  leadding to references to the filter instance that was then
  replaced in the subsequent eyeball attempts. That led to a use
  after free in the buffer handling for the transfer
- transfers are initiated now more lazy (like in the ngtcp2 filter),
  when the stream is actually opened
- suppress reporting on quiche event errors for "other" transfers
  than the current one to not fail a transfer due to faults in
  another one.
- revert recent return value handling for quiche_h3_recv_body()
  to not indicate an error but an EAGAIN situation. We wish quiche
  would document what functions return.

Fixes #11449
Closes #11469
Reported-by: ウさん