Add tests for queries with denormalized links

[Floriferous]

Queries with denormalized links fail in all sorts of ways, there's a lot that breaks.

I added a couple tests that highlight the kinds of things that fail, and tried to make a change that helps with reducing the issue, but is not nearly good enough.

Basically, combining grapher-caches with reducers and real caches does not work:

// This query
comments: {
  author: { name: 1 },
  authorCache: 1, // There's more data in the cache
}

// Returns this data:
comments: {
  _id: 1,
  authorId: 1,
  author: { } //  full cache data here, should only have name
  // Missing authorCache
}

With my initial fix:

// This query
comments: {
  author: { name: 1 },
  authorCache: 1,
}

// Returns this data:
comments: {
  _id: 1,
 authorId: 1,
 author: { } //  full cache data here, should only have name
 authorCache: { } //  full cache data here, is correct
}

Todo:

• Fix all the new tests
• Probably add more denormalization-related tests, since none exist at the moment

[StorytellerCZ]

@Floriferous would you be so kind to update this to the latest master? Thank you!

[StorytellerCZ]

Did a merge in my branch, here are the failing tests: https://github.com/StorytellerCZ/grapher/actions/runs/3810463294/jobs/6482555473