transcoding: Add capability check for transcoder tests am: e6ec13b662 am: 96f2e654c7 am: 2662961e4b

Original change: https://googleplex-android-review.googlesource.com/c/platform/cts/+/15716916

Change-Id: I576c06935a472cd3960bfac5f39c222b51251b28