Make gl-native handling of newlines conform to gl-js behavior

[ChrisLoer]

When I ported my recent gl-native line breaking changes to gl-js, I found that gl-js has tests for labels with newlines in them (https://github.com/mapbox/mapbox-gl-js/blob/master/test/js/symbol/shaping.test.js). The gl-js tests expect each newline to cause a new line to be created, while gl-native will just treat them like whitespace (so two newlines in the middle of your label will be collapsed down to just one breaking point instead of inserting a blank line).

I'm not sure when we would expect labels to have newlines in them, but we should probably standardize on one behavior or the other.

cc @ansis @1ec5

[1ec5]

The GL JS behavior sounds more correct.

[ChrisLoer]

Ah, I just had to look through the file history to see it was recently added as an enhancement: mapbox/mapbox-gl-js#955

[ChrisLoer]

I'll address this with a port of mapbox/mapbox-gl-js#3743 to gl-native. I have the code ready, but waiting for the first PR to go in before making a new PR to keep the test changes from conflicting.

[1ec5]

This is happening in #7446.

[ChrisLoer]

Closed with #7446.