Add jgruber@chromium.org as a compiler owner.

Change-Id: I333ceca8c811c32dd6c7cad941082ca7a87a985e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1826718Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63980}

src/compiler/OWNERS

@@ -8,6 +8,7 @@ tebbi@chromium.org
 neis@chromium.org
 mvstanton@chromium.org
 mslekova@chromium.org
+jgruber@chromium.org
 
 per-file wasm-*=ahaas@chromium.org
 per-file wasm-*=bbudge@chromium.org