Provide an API to snapshot views while avoiding animations

[BrianGardnerAtl]

Some views complete rendering after an animation, such as the OutlinedTextField (referenced in #1032). Calling the regular snapshot functions will only grab the first frame which shows the view in an incomplete state. It would be nice to have an API that allowed snapshotting a view after an animation, potentially by specifying a number of frames to skip before taking the snapshot.