DIsable spotlight indexing and add retry to homebrew tests

What does this MR do?

see title

Why was this MR needed?

We're seeing random timeouts when running brew tests. Since it impacts all the formulas randomly, we're thinking it might be a disk problem. Spotlight indexing runs at startup and adds load to the disk when we run the tests (and also when customers run tests), so it should be disabled in any case.

Since it appears it can get re-enabled by software updates. We have to add the task to all roles where we execute from snapshots.

Adding the retry on the affected OSes to see if that provides relief, even though it might slow down our pipelines. THis is to allow us to get a green master build

What's the best way to test this MR?

What are the relevant issue numbers?