getBounds() gives incorrect result when rotating

[zoltan-mihalyi]

mapbox-gl-js version: 0.23.0 - 0.46.0
It worked in 0.22.0. I'm suspicous to this commit: 06c3e1f

browser: chrome

Steps to Trigger Behavior

1. rotate the map
2. call map.getBounds()

In example:

1. rotate the map
2. the rectangle is the result of getBounds() call

Link to Demonstration

https://jsfiddle.net/og5tbcLn

Expected Behavior

getBounds() should return a LngLatBounds covering the viewport.

Actual Behavior

getBounds() returns a LngLatBounds covering bottom-left and top-right points of the viewport, but excluding bottom-right and top-left.

demo without the bug, with older version: https://jsfiddle.net/kmmky7h5/