False-positive unused import on controller in its spec

I have code of this form in a Grails (2.5.6) project:

```groovy
import MyController
import grails.test.mixin.TestFor
import spock.lang.Specification

@TestFor(MyController)
class MyControllerSpec extends Specification { ... }
```
The import of the controller is reported as unused by the resp. inspection, but Optimize Import does not remove it:

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Since the import is _not_ obsolete, it shouldn't trigger the warning.

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*Imported from [IDEA-201195](https://youtrack.jetbrains.com/issue/IDEA-201195) · Type: Bug · Votes: 0*
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Reproduce the case in a Grails 2.5.6 project using a controller spec with @TestFor(MyController), then trace the unused-import inspection's handling of that annotation. Done means the controller import is no longer reported as unused and Optimize Import continues to preserve it.

Written by the indexing model from the issue text.