Use POSIX APIs directly in quic_client_test

The code in question already heavily relies on Linux specifics, so we might as
well use them in order to avoid adding extra platform layers.

Merge internal change: 232956193

R=rch@chromium.org

Change-Id: I190deadc85fd55a717f8c78f373978112370146f
Reviewed-on: https://chromium-review.googlesource.com/c/1460075
Reviewed-by: Ryan Hamilton <rch@chromium.org>
Commit-Queue: Victor Vasiliev <vasilvv@chromium.org>
Cr-Commit-Position: refs/heads/master@{#630350}
1 file changed