Additional web-platform-tests for nested workers

Bug: 31666
Change-Id: Ib4e935437d0bf08fabc6c83103e6979e1c7ac8c8
Reviewed-on: https://chromium-review.googlesource.com/1104953
Commit-Queue: Nate Chapin <japhet@chromium.org>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568666}
15 files changed