Previously, cases like:
```dart
Color.lerp(const Color(0xFF00FF7F), const Color(0xFF00FFFF), 1.1)
```
...would result in unexpected effects (in this instance, lerping
between these colors with a curve that overshoots would take what
should be a simple animation from pale green to blue and add some
flickering bright green whenever it overshoots).
ccf9859b0d