The elastic#127318 changed the behaviour of `client()` to not start a node if there
is none found in the cluster. Which also changed the `getMasterName()`
behaviour to simply fail if there are no nodes instead of starting one.

This is why the `getMasterName()` is failing now. There were no nodes
started because the test scope is set to manually manage master nodes
(`autoManageMasterNodes = false`) without data nodes (`numDataNodes = 0`).

The fix is to actually start the master node instead of attempting to get
the master node name from an empty cluster and depend on a side effect
to actually boostrap a node.

Additionally it awaits for the master node to process all cluster state events
before proceeding, which should hopefully solve the original cause of failures.

Resolves elastic#120964
Resolves elastic#120923

(cherry picked from commit ee6d64a)

# Conflicts:
#	muted-tests.yml