[blink perf_tests] Add myself as an OWNER

It would be great if I could review changes like
https://chromium-review.googlesource.com/c/chromium/src/+/1352339
since I am taking ownership of benchmarking project as a whole.

Change-Id: I9c7b65adb5e18e30c6b9c6cdf1fb9f74ff064aea
Reviewed-on: https://chromium-review.googlesource.com/c/1351561Reviewed-by: Ned Nguyen <nednguyen@google.com>
Commit-Queue: Caleb Rouleau <crouleau@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611330}

third_party/blink/perf_tests/OWNERS

 haraken@chromium.org
 hayato@chromium.org
 nednguyen@google.com
+crouleau@chromium.org
 
 # Team: benchmarking-dev@chromium.org
 # COMPONENT: Speed>Benchmark