Summary:
- Also move out reused helper methods out of test suites, to avoid inadvertently including some test suites into other suites.
- Add logging around onNewTab since that seems related to test failures.
- Skip several tests in Billing that fail particularly often.
Test Plan: Checking that tests pass, and how many. Compared to the last successful run on master, there are 4 new skips (this diff), and 3 fewer test cases (a test case run in triplicate was removed in https://github.com/gristlabs/grist-core/pull/899)
Reviewers: georgegevoian
Reviewed By: georgegevoian
Differential Revision: https://phab.getgrist.com/D4216
