Fix recent flake in DtlsRestartOneCalleAtATime

Also fix typo in the test name. Was tempted to s/Calle/Kalle but settled
on the less entertaining s/Calle/Callee.

DISABLE_SPELLCHECKER: true

Bug: none
Change-Id: Ia5462c363587fd4b5a58f5865f9cd015529a828d
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/417840
Commit-Queue: Tomas Gunnarsson <tommi@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Auto-Submit: Tomas Gunnarsson <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#45958}