Running Error Prone over Maven triggers an infinite recursion
check in AbstractCoreMavenComponentTestCase.PluginBuilder; on
inspection, the class is unused. Remove it, along with the commented-
out (since bc257a5) reference to it.

Running Error Prone over Maven triggers an infinite recursion
check in AbstractCoreMavenComponentTestCase.PluginBuilder

The MNG-7706 deprecates ancient ArtifactRepository type use to get access to local repository, and issues warning as for any other deprecated Mojo parameters.

But alas, in ITs the MNG-5576 completely unrelated IT there is an assertion to have WARNING-free log. This IT uses the IT-plugins/IT-plugin-expression EvalMojo, that in turn uses the deprecated `${localRepository}` parameter (but does not use it). Result is, Maven 3.9.1 emits a WARNING about use of deprecated parameter and the IT fails.

Further inspection shows, that while EvalMojo injects ArtifactRepository for local repository, there is only one IT that actually uses it, the MNG-4305, but even that one is interested in basedir of the local repository only. So to say, the use of deprecated ArtifactRepository type is not needed at all.

Fix:
* change EvalMojo to not expose in context the localRepository (w/ type ArtifactRepository), but a new expression `localRepositoryBasedir` only, that is injected in non-deprecated way (in real life repoSysSession would be injected, but in IT we keep all super-safe and use Object types).
* adjusted MNG-4305 to use new epxression instead to use object reflection in template to get basedir from ArtifactRepository
* This makes the originally failing MNG-5576 pass, as warning due EvalMojo is gone.

See
https://issues.apache.org/jira/browse/MNG-7706
apache#1009