These might be useful for a function with a more restricted domain. But for
equals, which accepts two of literally anything, the short run was too short
to catch any problems and the long run tended to exceed the CircleCi timeout.
* Don't run them in browsers in the regular CI build
* Run them in browsers in a special nightly build
* Run them in Node in the regular CI build
* Run them when developers manually run the suite
This should allow the regular CI build to give us a more useful signal,
while keeping us from losing sight of the flaky specs.
