[Tests] add different node name prefix for the different cluster type

During a test run we have a global shared cluster and potentially a suite level or even a test level cluster running. All of those share the same node name pattern (node_#). This can be confusing if you're debugging discovery related tests where those nodes from the different clusters potentially interact (and reject each other). This commit gives each cluster type a unique prefix to make tracing and log filtering simpler.

Closes #7518