This makes it not an error to bind a SequenceChecker before the
global TaskQueueBase::Current() is set.
Unbreaks the SDP integration fuzzer.
Bug: webrtc:13374
Change-Id: Ic4c23fa29f4598290cf9196550e5133ba753f44f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/237620
Reviewed-by: Niels Moller <nisse@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35341}