Remove definition of thread annotation macros without RTC_ prefix

BUG=webrtc:8198

Review-Url: https://codereview.webrtc.org/3007363002
Cr-Original-Commit-Position: refs/heads/master@{#19810}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 47791cf0f8400984c0e90229c756e404ba7eee4f
3 files changed