MNT Fix unit tests for kitchen-sink

[emteknetnz]

Issue #10278

Should fix some of the travis errors in https://app.travis-ci.com/github/silverstripe/recipe-kitchen-sink/jobs/567740337 which only happen in recipe-kitchen-sink (not installer) due to interactions with other modules

[GuySartorelli]

This looks okay but I don't really understand what this is changing - could you put a few words about how this is fixing the tests? I wanna just make sure it's not hiding legitimate failures.

[emteknetnz]

The change in setup means that calls in different tests to Director::forceWWW() and Director::forceSSL() don't carry over to other tests. They get reset between tests because setup() is run directly before each test.

The change in testRequestFilterInDirectorTest() is directly updating the middlewares in the Director singleton. Previously it was updating Injector so that (I think) when the Director singleton was instantiated for the first time it use the middlewares in config. I think what may have been happening is that something in one of the kitchen-sink modules was instantiating Director before the change in config.

In both of these instances, these tests do no fail on installer, only recipe-kitchen-sink. I wish I had more insight into why exactly this is happening, though I was unable to work out what was causing this.

[GuySartorelli]

Seems good to me, and the explanation makes sense. These changes are effectively making configuration for this test not affect other tests.