DRIVERS-943 Convert retryable writes command construction tests to unified format

[isabelatkinson]

DRIVERS-943

This PR removes the retryable writes command construction tests that assert on the presence/absence of txnNumber and adds equivalent assertions to the unified tests. Most of the existing retryable writes unified tests don't currently use command monitoring, and I only added what was necessary to match the coverage of the removed construction tests. DRIVERS-2849 tracks adding more comprehensive command monitoring assertions to the retryable writes tests.

Draft PR for Rust: mongodb/mongo-rust-driver#1234

The unacknowledged writes and collection bulk write tests are not run in the Rust driver, so another driver will need to verify that these tests work.

Please complete the following before merging:

• Update changelog.
• Test changes in at least one language driver.
• Test these changes against all server versions and topologies (including standalone, replica set, sharded
  clusters, and serverless).

[aditi-khare-mongoDB]

I feel this wording is a little confusing - originally it made me think we are no longer asserting on txnNumber.

I think it'd be better to remove this section, and if we want to include this information somewhere, we can expand in the changelog instead. Something like the following:

Convert command construction tests to unified format. In the retryable writes unified tests, the unified spec runner now asserts on the absence or presence of the txnNumber field using 'Command Monitoring'.

What do you think?

[isabelatkinson]

The specs README states:

Outdated tests must not be removed completely, but may be marked as such (e.g. by striking through or replacing the entire test with a note (e.g. Removed).

I think it's useful to maintain this section as a reference for drivers that have not yet removed these tests. WDYT about adding a strikethrough to the section title and rephrasing this as:

These prose tests have been removed in favor of unified format tests.

[aditi-khare-mongoDB]

Sure, we can also rephrase it to something like.

In the retryable writes unified tests, the unified spec runner now asserts on the absence or presence of the txnNumber field using 'Command Monitoring'.

This or the strikethrough works!

[kevinAlbs]

LGTM with suggestions applied. Tests pass in C driver.

---

DRIVERS-943 includes:

also move the Split Batch Tests section to a numbered prose test.

Though I prefer leaving that change out of this PR (as is done now). I expect that can be done in a separate PR if that is still desired, and may not require a DRIVERS ticket.

[kevinAlbs]

Suggest splitting to test updateMany and deleteMany in isolation:

  - description: "collection bulkWrite with updateMany does not set txnNumber"
    operations:
      - object: *collection0
        name: bulkWrite
        arguments:
          requests:
            - 
              updateMany:
                filter: {}
                update: { $set: { x: 1 } }
    expectEvents:
      - client: client0
        events:
          - commandStartedEvent:
              commandName: update
              command:
                txnNumber: { $$exists: false }
  - description: "collection bulkWrite with deleteMany does not set txnNumber"
    operations:
      - object: *collection0
        name: bulkWrite
        arguments:
          requests:
            - 
              deleteMany:
                filter: {}
    expectEvents:
      - client: client0
        events:
          - commandStartedEvent:
              commandName: delete
              command:
                txnNumber: { $$exists: false }

[isabelatkinson]

@aditi-khare-mongoDB do these tests pass in the Node driver?

[isabelatkinson]

The specs README states:

Outdated tests must not be removed completely, but may be marked as such (e.g. by striking through or replacing the entire test with a note (e.g. Removed).

I think it's useful to maintain this section as a reference for drivers that have not yet removed these tests. WDYT about adding a strikethrough to the section title and rephrasing this as:

These prose tests have been removed in favor of unified format tests.

[aditi-khare-mongoDB]

See comment! LGTM with changes