The test is hidden behind the `@Ignore` annotation due to some
flakiness. However, it will be removed when the subtitle parsing is
moved to a pre-sample-queue architecture.
The test media was created with:
```shell
$ cp ../../dash/standalone-ttml/sample.xml sample.ttml
$ MP4Box -add sample.ttml sample.text.mp4
$ MP4Box -frag 10000 sample.text.mp4
$ rm sample.ttml
```
PiperOrigin-RevId: 582347113
67f770a786