test: Divergent testing of _merge_object_divergent_entries() cases

test: Divergent testing of _merge_object_divergent_entries() cases

Case 1: A more recent update exists
Case 2: The first entry in the divergent sequence is a create
Case 3  NOT TESTED - Ohject currently missing
Case 4: We can rollback all of the entries
Case 5: We cannot rollback at least 1 of the entries

Support starting OSDs even when "noup" is set (don't wait for up).
Move create_ec_pool() to ceph-helpers.sh

Fixes: https://tracker.ceph.com/issues/39162
Signed-off-by: David Zafman <dzafman@redhat.com>