Currently, it is hard to tell which of the many sub-cases
fail in this unit test, in case any of them fails.
This change uses logging in debug and trace level
to help with that by reproducing the error
with --logger-log-level testlog=trace
(The cases are deterministic so reproducing should not
be a problem)
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>