Mark 2 tests as flalky with network service.

TBR=yzshen@chromium.org
NOTRY=true

Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: Ib0d6e8c8b8841dc32b5b5b4f81a5052e5dbb2f4a
Reviewed-on: https://chromium-review.googlesource.com/782080


Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#518276}