Remove COMMON_OWNERS from top-level OWNERS

Bug: v8:9247
Change-Id: Ieae700aa01261c712e3ac22967fe3c59988c25c6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1635892Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61959}

OWNERS

@@ -2,9 +2,6 @@
 # Disagreement among owners should be escalated to eng reviewers.
 file://ENG_REVIEW_OWNERS
 
-# TODO(9247) remove this.
-file://COMMON_OWNERS
-
 per-file .clang-format=file://INFRA_OWNERS
 per-file .clang-tidy=file://INFRA_OWNERS
 per-file .editorconfig=file://INFRA_OWNERS