test(SFINT-3352): Safer tests

[louis-bompart]

Flaky UT issue from #86, see https://travis-ci.org/github/coveo/search-ui-extensions/builds/712557300.

I was not able to 'pin-point' with certitude what caused the flakiness, due to the issue being, well flaky (and thus I'm not 💯 confident it'll be fixed but I think it will)

Two fixes:

• Do not modify activateSpy and deactivateSpy they're used as default options for the component instantiation, which can cause test leakage.
• Ensure all events listener have completed their job before checking the spies. This also prevents test leakage (you could have the eventListener of the test n-1 executed during the execution of the test n) and also that we're actually testing what we want. (We do not want to 'miss' a double call because the second call occurs after the expectation.

[louis-bompart]

Promise.all and Jasmine cannot just cooperate (in fact, Jasmine and promises beyond basics are not working well together at all from what I experienced)

[nathanlb]

Are there any metrics you noted that confirm this helps? Even just a little bit

[louis-bompart]

Are there any metrics you noted that confirm this helps? Even just a little bit

Eye-balling mostly but 10-20% failure rate before, 0% after (never reproduce after my changes on +10runs)

[nathanlb]

Sounds pretty good to me