Summary:
Moves some more relevant tests to grist-core.
Small change to declarations that seemed necessary when
running buildtools/build_core.sh now, but I'm not sure
what changed. CI hasn't flagged anything, so smells like
the version of some package not nailed down.
Test Plan:
tried running tests in new location using
buildtools/build_core.sh
Reviewers: jarek
Reviewed By: jarek
Differential Revision: https://phab.getgrist.com/D3996
