[roll] Roll fuchsia [closure-queue] Use checker instead of thrd_t

This removes the thrd_t parameter and instead uses an
async::synchronization_checker. This enables use with dispatchers that
guarantee in-order serial execution but don't guarantee the same thread
for all dispatches.

At some point we may want to relax the requirement that the
synchronization_checker must be constructed on the dispatcher. It's a
common and valid pattern in C++ and other languages to construct on one
thread and then restrict usage and deletion to a separate thread or
serialized execution context. The switch to the dispatcher (and back)
to create the synchronization_checker isn't free, and the association
between synchronization_checker and the dispatcher could be achieved
in other/alternate ways that don't force a double thread switch. For
now this CL does introduce the requirement to construct or call
SetDispatcher while on the dispatcher, but only because
synchronization_checker demands to be constructed on the dispatcher,
not for any fundamentally necessary reason (contrast with before, where
we obtained the thrd_t during thread creation and didn't need to switch
to that thread during construction).

Original-Original-Bug: 478359574
Original-Original-Bug: 482514220
Multiply: fuchsia-pkg://fuchsia.com/audio_encoder_test#meta/audio_encoder_test.cm
Original-Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1498677
Original-Original-Revision: 6bddddb3382f665a55e55b1b5bc3301490ef7232
GitOrigin-RevId: a219686999b54114ac1b8588d459c324ae2066d1
Change-Id: I6f8a575763641ee1bb7c9f5acce608cfdb18e43e
Reviewed-on: https://fuchsia-review.googlesource.com/c/integration/+/1644355
Cr-Commit-Position: refs/heads/main@{#194380}