test(NODE-3710): sync max srv hosts tests

[durran]

Description

Syncs tests for limiting the number of MongoDB hosts a SRV record can return.

What is changing?

Adds the initial DNS seed discovery tests to support the new feature.

Is there new documentation needed for these changes?

No

What is the motivation for this change?

Syncing tests in order to implement the feature.

Double check the following

• Ran npm run check:lint script
• Self-review completed using the steps outlined here
• PR title follows the correct format: <type>(NODE-xxxx)<!>: <description>
• Changes are covered by tests

[dariakp]

I see in the spec repo, these tests are all in subfolders, e.g., load-balanced, replica-set. I think keeping them in the same directories instead of flattening would help ensure we actually pull in all the changes and keep things up to date in the future. In the spec commit, there are 48 changed files, subtracting the 4 actual spec modifications, that's 44 files, 42 of which are yml/json, but I only see 32 in this PR, so I think we are missing some changes.

Also, I think it would be worth pulling in https://jira.mongodb.org/browse/NODE-3696
these spec changes into the PR, so that we are working off the correct set of expectations for the uri-options tests from the get-go (see this spec commit)

[durran]

Updated uri options tests to NODE-3696, and changed the directory structure to match the spec tests and resynced.