Understand hamcrest-core 2.2

### Affected version

HEAD

### Bug description

```

org.hamcrest
hamcrest-core
2.2
test

```

This one's an ugly mess. It has a purpose when present to avoid introducing a transitive dependency on hamcrest-core 1.3, which can happen with JUnit 4. However, it's just a shim that contains no classes and depends on hamcrest.

This creates one of the ugly unused when included and needed when not included warning Catch-22s.

In any case we should never report hamcrest-core 2.2 as unused. It contains nothing, causes no problems, and prevents other problems even though it contributes exactly zero classes to the classpath.

The issue identifies the hamcrest-core 2.2 test dependency and the unused-dependency warning as the target, but names no source file, test, or entry point. First locate the analyzer path that emits unused-dependency reports and its regression tests for dependency scopes; done means hamcrest-core 2.2 is not reported unused while ordinary unused dependencies remain covered.

Written by the indexing model from the issue text.