Switch on android.telecom.Log in Telecom

Move over the Runnable Class into android.telecom and turn on the
framework's usage in Telecom.
CP from: https://android-review.googlesource.com/#/c/287291/

Test: All Telecom unit tests pass. Manual Log testing has also been
confirmed to be working as it did before.
Bug: 26571395
Change-Id: If7e2036c746c5a953f3a77e2d625a423ce5bf8f3
(cherry picked from commit 9fbbd405)