Revert of Reland "Add first part of the network_tester functionality" (patchset #3 id:40001 of https://codereview.chromium.org/2808203003/ )

Reason for revert:
Break downstream bots.

Original issue's description:
> Reland "Add first part of the network_tester functionality"
>
> BUG=webrtc:7426
>
> Review-Url: https://codereview.webrtc.org/2808203003
> Cr-Commit-Position: refs/heads/master@{#17666}
> Committed: https://chromium.googlesource.com/external/webrtc/+/1c223b2f7557ff449add7a114d72ea97614731b5

TBR=stefan@webrtc.org,minyue@webrtc.org,nisse@webrtc.org,terelius@webrtc.org,michaelt@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7426

Review-Url: https://codereview.webrtc.org/2813193002
Cr-Original-Commit-Position: refs/heads/master@{#17672}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: e5fd38989de6900cd32e7c88932201ec3b3467d8
13 files changed