[Trusted Types] Work-around for TrustedTypes accessor confusion.

This (temporarily) renames workers' TrustedTypes to TrustedTypesWorkers,
in order to work around a suspected issue with the current Origin Trial.
It also removes several DHCECKS, which were incorrect in the presence
of Origin Trials. Additional details can be found in the bug.

Bug: 959693
Change-Id: I8169f20ba61d98a55e5387cd27045ce7bf8e7579
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1620625
Reviewed-by: Mike West <mkwst@chromium.org>
Commit-Queue: Daniel Vogelheim <vogelheim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#662287}
7 files changed