[test262] Remove myself from OWNERS

I haven't done any test262 rolls in forever and won't be doing any for
the foreseeable future, there's no need for me to be an OWNER.

Change-Id: I51d5915f5704d0c15c0735c95cfbff9464a0e929
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2632592
Auto-Submit: Sathya Gunasekaran  <gsathya@chromium.org>
Reviewed-by: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72117}

test/test262/OWNERS

 adamk@chromium.org
-gsathya@chromium.org
 syg@chromium.org