Fix TechChange's assumption about TextView targets

Some of the code in the TextChange transition assumed that the
start values for a transition were for a TextView object. This may
not be the case, and we should return early (without creating an
animator) when it is not.

Issue #10725388 Frequent Framework crashes across apps

Change-Id: I6999eb2288f107f4b93ddb5b77cd068069d831ed