Make tail work with file rotation when using polling file watcher

If `Poll=true`, then log rotation interferes will the tail operation. This is because `PollingFileWatcher` does not recognize when a file was recreated (inode change). There are other issues with PollingFileWatcher, and this is understandable as only the Inotify watcher was tested against file rotation. This pull requests fixes it along with a test case to verify it.