Add compatibility test for $position

[eerxuan]

Part of #37.

Category: core / operator / update / modifiers

Add compatibility test coverage for the position feature.

Note: a smoke test exists; comprehensive compatibility test coverage is needed.

[vic-tsang]

/take

[github-actions]

Assigned to @vic-tsang!

[documentdb-triage-tool]

👋 @vic-tsang — this issue has been assigned for 14 days with no activity. Is it still in progress? If you've made progress, please leave a quick update. Otherwise it'll be flagged for re-assignment at the next triage meeting.

[documentdb-triage-tool]

👋 @vic-tsang — this issue has been assigned for 14 days with no activity. Is it still in progress? If you've made progress, please leave a quick update. Otherwise it'll be flagged for re-assignment at the next triage meeting.

[documentdb-triage-tool]

👋 @vic-tsang — this issue has been assigned for 14 days with no activity. Is it still in progress? If you've made progress, please leave a quick update. Otherwise it'll be flagged for re-assignment at the next triage meeting.

[eerxuan]

Comprehensive compatibility tests now exist beyond the smoke test; closing.