[OWNERS] Add cbruni@chromium.org to more OWNERs files

Change-Id: Icb77604d55353064cb793224b3f9c5b691503852
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3466794Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Auto-Submit: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79121}

src/codegen/OWNERS

+cbruni@chromium.org
 clemensb@chromium.org
 gdeepti@chromium.org
 ishell@chromium.org

src/roots/OWNERS

 bmeurer@chromium.org
+cbruni@chromium.org
 hpayer@chromium.org
 ishell@chromium.org
 jgruber@chromium.org