[ci] Add MultiInstance_Startup_Checks_2004 check

[zach2good]

I affirm:

• [x] that I agree to Topaz Next's Limited Contributor License Agreement, as written on this date
• [x] that I have read the Contributing Guide and the Code of Conduct
• [x] that I've tested my code since the last commit in the PR, and will test after any later commits

Add multi-instance startup check to CI

TODO: Use dbtool for initial setup