* Remove redundant closure passings.
* Enforce use of "$" (not 'jQuery').
* Enforce use of "mw" (not 'mediaWiki').
* Use blacklist instead of whitelist for ESLint config.
This means ESLint is now enabled on test/, which was previously
missing (by accident?).
* Add eslintrc for test/ as needed to disable two style rules
currently violated.
* Fix violations of 'qunit/no-negated-ok'.
Bug: T208951
Change-Id: Ib995090804a98dda71b8574609e84561371c8c0c