Add mathias@chromium.org as DEPS owner for Test262 rolls

NOTRY=true

Bug: v8:7834
Change-Id: Ifc6c807d19d10b447aab6c4f21c1a640fe4f3a10
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1695468
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Auto-Submit: Mathias Bynens <mathias@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62618}

OWNERS

@@ -13,6 +13,8 @@ per-file .vpython=file://INFRA_OWNERS
 per-file .ycm_extra_conf.py=file://INFRA_OWNERS
 per-file BUILD.gn=file://COMMON_OWNERS
 per-file DEPS=file://INFRA_OWNERS
+# For Test262 rolls.
+per-file DEPS=mathias@chromium.org
 per-file PRESUBMIT=file://INFRA_OWNERS
 per-file codereview.settings=file://INFRA_OWNERS