Permanently disable xss auditor.

Minimal code change to get new behaviour so that tests can
be updated. Code cleanup in a subsequent CL.

The third_party/blink/web_tests/http/tests/security/xssAuditor
directory is removed entirely. Three other files outside this
directory are removed which also triggered the auditor.

Bug: 968591
Change-Id: I6374a4c381c8a5210eaff97c8f031a789c7059b7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1723805
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Mike West <mkwst@chromium.org>
Cr-Commit-Position: refs/heads/master@{#684138}
518 files changed