HV-907 Fixing unwanted generated classes after build

> why do we only get the problem for two specific model classes? Just trying to understand.

These two model classes are the only ones that actually compile. The others have some annotations errors that prevent them from compiling, so we don't see their `.class` files. Note that `FieldLevelValidationUsingBuiltInConstraints` has errors, but it's compiled with `Kind.WARNING` in `#testThatProcessorOptionsAreEvaluated`.

As to why `options.addAll( Arrays.asList( "-d", "target" ) );` is not enough, I'm not really sure. We can remove these lines:

    fileManager.setLocation( StandardLocation.CLASS_PATH, getDependenciesAsFiles( dependencies ) );
    fileManager.setLocation( StandardLocation.CLASS_OUTPUT, Arrays.asList( new File( "target" ) ) );

Then there will be no extra class files, but HV-575 test will fail.

My best guess is if we specify a location in the `fileManager`, then it will take priority over the `-d` option.