In this patch, we remove 3 tests:
1. test for blocked domain
2. test for blocked sub-domain
3. test for non-blocked domain
Two nsIDOMWindowUtils APIs were added for adding/removing a mock domain to the
existing blocklist. They are only used in the Stylo blocklist tests, so we
remove them as well.
MozReview-Commit-ID: A0ETWlqwbpN