Linkage Checker to show location of outer class if any

As of now, Linkage Checker does not show the location of JAR file for missing class, even when the class is an inner class.

Example in https://gist.github.com/suztomo/a9e5d46dc64bd19967c6762a468c9b66

```
Class com.google.api.client.http.apache.ApacheHttpTransport$Builder is not found;
referenced by 1 class file
com.google.cloud.hadoop.util.HttpTransportFactory (util-1.9.16.jar)
```

Here, it's helpful if it shows the location (JAR file) of `com.google.api.client.http.apache.ApacheHttpTransport` class.