Merge "Set up libtextclassifier_tests into MTS" into rvc-dev am: 0bce29a225 am: be3c7b5e56 am: cb282190bc

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

Change-Id: Ie24aa0b4963332a933857a03e03aab47ea1097c7