Revert of Rename thread annotation macros to have RTC prefix for syncrhonization primitives. (patchset #1 id:1 of https://codereview.webrtc.org/3004393002/ )

Reason for revert:
Breaks chromium bots

Original issue's description:
> Rename thread annotation macros to have RTC prefix for syncrhonization primitives.
>
> other macros (e.g. GUARDED_BY) rename postpone to followup CL
> since it touches codebase wider
>
> BUG=webrtc:8198
>
> Review-Url: https://codereview.webrtc.org/3004393002
> Cr-Commit-Position: refs/heads/master@{#19701}
> Committed: https://chromium.googlesource.com/external/webrtc/+/9a2d2dd973ea33ba551db09257441c7f6943bfe4

TBR=kwiberg@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:8198

Review-Url: https://codereview.webrtc.org/3008193002
Cr-Original-Commit-Position: refs/heads/master@{#19702}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 42a70e31d6b08355e5803f66433b043d5825b56f