Revert "Disabled TestPacketBuffer.SeqNumWrapOneFrame test due to clang update"

This reverts commit 03c592a1e9f9dbad02bfc9d1f55d8b8c5c499208.

Reason for revert: Problem with clang should be solved now

Original change's description:
> Disabled TestPacketBuffer.SeqNumWrapOneFrame test due to clang update
> 
> Until further investigation.
> Clang update: chromium:880827
> 
> Bug: chromium:887464
> Change-Id: Id1fe85a013920e6ae8c6ac69efb0a0502b9dd6fe
> Reviewed-on: https://webrtc-review.googlesource.com/101561
> Commit-Queue: Artem Titarenko <artit@webrtc.org>
> Reviewed-by: Artem Titarenko <artit@webrtc.org>
> Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#24795}

TBR=phoglund@webrtc.org,artit@webrtc.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: chromium:887464
Change-Id: Id4d1722b289d9f56ae2aebf576f28f3b02a4c942
Reviewed-on: https://webrtc-review.googlesource.com/c/108583
Reviewed-by: Artem Titarenko <artit@webrtc.org>
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Commit-Queue: Artem Titarenko <artit@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25428}