For simplicity this CL includes a first crude conversion of
tickprocessor.mjs. Later CLs will introduce more ES6 syntax and clean
up more code.

Bug: v8:10667
Change-Id: Ief2ca623f5562114fb976a95d156e2ab3f961114
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2611252Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72013}