Add WPT tests for clients.claim() of Dedicated Worker and Shared Worker

We need these tests to cehck the behavior of WorkerFetchContextImpl::SetControllerServiceWorker()

Bug: 443374
Change-Id: I6c8c7df133be41105c3394c16009cae0b110d8f9
Reviewed-on: https://chromium-review.googlesource.com/620469
Commit-Queue: Tsuyoshi Horo <horo@chromium.org>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#495876}
6 files changed