fix: disable parallelization of surrealdb conformance tests

[Odonno]

Fixes #974

PR Checklist

• Created a feature/dev branch in your fork (vs. submitting directly from a commit on main)
• Based off latest main branch of toolkit
• PR doesn't include merge commits (always rebase on top of our main, if needed)
• Contains NO breaking changes
• Every new API (including internal ones) has full XML docs
• Code follows all style conventions

Other information

[Odonno]

For context, CollectionDefinition only seem to work with child class and not the base class.

[aaronpowell]

Is that why they haven't been shutting down properly?!

[Odonno]

Yes, I reproduced the issue locally and this code fixes it.