When an index is created without an explicit name, a default name
is chosen. However, there was no check if a table with conflicting
name already exists. The check is now in place and if any conflicts
are found, a new index name is chosen instead.
When an index is created *with* an explicit name and a conflicting
regular table is found, index creation should simply fail.
This series comes with a test.
Fixes#8620
Tests: unit(release)
Closes#8632
* github.com:scylladb/scylla:
cql-pytest: add regression tests for index creation
cql3: fail to create an index if there is a name conflict
database: check for conflicting table names for indexes
cee4c075d2