cql-pytest: add regression tests for index creation
cql-pytest: add regression tests for index creation

This commit adds unit tests for an issue with index creation
after a table with malicious name is previously created as well.
The cases cover both indexes with a default name and the ones with
explicit name set.

scylladb/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla