Also fully deprecate AbortTracing.

Bug: chromium:843903
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: I852d28d8ce0f02b3a048b1061de29c9fce71ce62
Reviewed-on: https://chromium-review.googlesource.com/c/1278811
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56655}