Rationalize master extension integration testing

[jamesnetherton]

Description

Not sure why we have integration tests for master & master-file.

The only difference seems to be the master test manually configures the FileLockClusterService, whereas with master-file, it's done via the file-cluster-service extension.

I don't see the need to test both scenarios. The preferred way is to always use the -cluster-service extensions. So we can drop master and build up a suite of master-* test modules to test the various cluster services.