Style fill-pattern does not switch based on feature-state

[justenPalmer]

When using fill-pattern expressions, the resulting fill does not correctly switch based on feature-state.

mapbox-gl-js version: 50.0

browser: Chrome 69.0.3497.100

Steps to Trigger Behavior

1. Create a layer with a fill-pattern expression which switches based on feature-state
2. Set the feature-state for a visible feature
3. Observe that the fill-pattern does not change for the feature

Link to Demonstration

In the above example, there are two layers which switch style based on feature state from the same source-layer. The first has the expression in "line-color" which works as intended. The second has a "fill-pattern" with the exact same logic, but does not execute correctly.

https://jsbin.com/qidikopure/edit?html,output

Expected Behavior

The feature with the set state should appear with a diagonal red line pattern

Actual Behavior

The feature with the set state has the default dotted pattern

[asheemmamoowala]

Duplicate of #7207