Merge 'pytest: start after ungraceful stop' from Alecco

If a server is stopped suddenly (i.e. not graceful), schema tables might
be in inconsistent state. Add a test case and enable Scylla
configuration option (force_schema_commit_log) to handle this.

Fixes #12218

Closes #12630

* github.com:scylladb/scylladb:
  pytest: test start after ungraceful stop
  test.py: enable force_schema_commit_log