Make rtc::TimestampWrapAroundHandler handle backwards wrapping

Also fix a timestamp issue in video analyzer test.

BUG=webrtc:5637, webrtc:5537

Review URL: https://codereview.webrtc.org/1779773002

Cr-Original-Commit-Position: refs/heads/master@{#11938}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 1b3530b4df1dc5ef3a6c16b41d86dd910d24c573
3 files changed