Update common owners to include zhin@, and remove titzer@

Change-Id: I85d995e46577712ba7e6a3a4d55f397c09867a4b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2079344Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66491}

COMMON_OWNERS

@@ -32,7 +32,7 @@ solanes@chromium.org
 syg@chromium.org
 szuend@chromium.org
 tebbi@chromium.org
-titzer@chromium.org
 ulan@chromium.org
 verwaest@chromium.org
 yangguo@chromium.org
+zhin@chromium.org