Worker: Run http/tests/workers/ with off-the-main-thread top-level dedicated worker script fetch

Bug: 835717
Change-Id: Icde42b1dd837ca6110933b5cffc53864b7778a0d
Reviewed-on: https://chromium-review.googlesource.com/c/1364811
Reviewed-by: Makoto Shimazu <shimazu@chromium.org>
Commit-Queue: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614280}
3 files changed