Initialize constant MatrixMotivators properly.
Initialize constant MatrixMotivators properly.

We were relying on BlendToOp() to be called, and if it
wasn't we'd get an assert in the BulkSplineEvaluator.

This was causing matrix_test to fail.

Change-Id: I6d0d0d894d2b86e881a2503dd71f9a0e9dbf5232
Tested: matrix_test now passes on Linux.

google/motive,google/motive