Add per-file Site Isolation owners to chromium.fyi.json.
Add per-file Site Isolation owners to chromium.fyi.json.

We'll use this to manage the list of tests on the Site Isolation FYI bots.

BUG=417518

Review URL: https://codereview.chromium.org/1416223003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#356916}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk