Features flash when transitioning between expression + constant values

[lbud]

mapbox-gl-js version: 0.44.2

browser: Chrome 65.0.3325.181

Steps to Trigger Behavior

1. Create a layer styled with a constant property.
2. Change property to expression-based property (not sure if all expressions, but at least with a match expression)
3. Styled properties flicker when switching between constant and expression-based properties.

Link to Demonstration

• https://jsfiddle.net/lbud/ar1c8trq/1/ : fill layer; mouseover/off features for disappearing flash (disappearing also happens for other layer types including line)
• https://jsfiddle.net/lbud/jfewqzdz/1/ : fill-extrusion layer; mouseover/off features for flash of black

Expected Behavior

Previously calculated paint values remain rendered until the first frame when recalculated values are ready, so there is no intermediary flash of any other value besides the two specified

Actual Behavior

Flash of either transparent or black

cc @anandthakker @kalimar

[anandthakker]

Likely due to #4012