Return 1f in Log(Ac/De)celerateInterpolators on a 1f input.

In battery saver mode, animations skip directly to the final values.
For LogDecelerateInterpolator, however, an input of 1f outputs an
interpolated 0.99999994. This meant that the FirstFrameAnimatorHelper
didn't realize that this was the last frame, and messed things up.
Since any interpolator should return 1 on an input of 1, we just
short-circuit in that case for the log interpolators.

Bug: 25666809
Change-Id: I60527e3758cea383fbcf50acb95460a7bd9ab43c
(cherry picked from commit 8dd24099)