Merge "Set up libtextclassifier_tests into MTS" into rvc-dev am: 0bce29a225 am: be3c7b5e56 am: 6ca2838547

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/libtextclassifier/+/11685296

Change-Id: I01044b46e4aacaf7ea6736415853fa0c504393bb