docker tests fixes

• Make the update part in tests optional so we can quickly run tests (the composer/npm etc. call should not normally be required since the webapp container does the initialization)
• migrate:refresh --seed during test init, so if we do opt in to reinit, we just force a full reinit.
• Exclude the same groups for all tests
• Stash local changes before running tests
• Run the testsuite in runchecks.sh
• Make sure any previous test containers are gone
• Get runchecks.sh to run selfcheck to validate the setup