Fix fuzz target owners file in case of renames and third_party.

- git --follow and --reverse don't work together. Just
  --follow is extremely slow, so use a best estimation
  with git blame on L1.
- For third_party, use OWNERS file to determine owners.
- Add skip_owners attribute to allow skipping of owners
  file.
- Fix review nits from last cl.

[email protected]
Bug:821574

Change-Id: I89fad0beae8a66ac3c6acfde0faa9b7d4be22383
Reviewed-on: https://chromium-review.googlesource.com/1030269
Reviewed-by: Max Moroz <[email protected]>
Reviewed-by: Jonathan Metzman <[email protected]>
Cr-Commit-Position: refs/heads/master@{#554164}
2 files changed