Fix bug preventing full map from rendering when viewport is < 512px
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**mapbox-gl-js version**: master
### Steps to Trigger Behavior
1. Create a map using, e.g., Mapbox Streets, in a div that is smaller than 512x512.
2. Zoom 'all the way out' (i.e. initialize the map to `center: [0, 0], zoom: 0`
### Expected Behavior

The whole world is shown.
### Actual Behavior

The whole world is not shown.

Repro: https://bl.ocks.org/anandthakker/raw/0e9afc1d09356f87449b5ffa3e49bd82/

## Relevant pre-fix discussion

### Issue #3055

#### Comment at 2019-04-11T02:32:58Z

Is preventing the entire world from appearing on small screens expected behavior?

I want to show clusters which span the entire world. It's a confusing UX to not have all the pins / clusters appear at once. 

This is how my map currently looks:
![Screen Shot 2019-04-10 at 7 30 28 PM](assets/mapbox__mapbox-gl-js-9028/001.png)


For reference, this is how mapbox.js + Leaflet handled this case:
![Screen Shot 2019-04-10 at 7 24 16 PM](assets/mapbox__mapbox-gl-js-9028/002.png)

There are some downsides to showing the full world.  Specifically, the grey area above and below the map look strange. I think the ideal option is to add a configuration value for disabling this behavior.

#### Comment at 2019-11-15T20:54:20Z

@supersteves That's correct. The 512 tile size is an internal architectural detail of GL JS. It is possible to have raster tiles of a different size (the Mapbox Satellite style uses 256 tiles for example) but we effectively scale them up by one so that at `0/0/0` you actually see 4 tiles that form a 512px view of the entire world, as shown below. GL JS isn't set up to display 256x256 tiles that display the entire world.

![Screen Shot 2019-11-15 at 12 51 05 PM](assets/mapbox__mapbox-gl-js-9028/003.png)

#### Comment at 2019-11-27T04:20:54Z

@supersteves @charliemcgrady @krispy-visokio @juho-hanhimaki @eddydg 

Thanks for providing your feedback on this issue! We have a proposal up that renders maps with the camera at a negative zoom levels (up to `-2`) in containers <512px when zoomed out all the way: https://github.com/mapbox/mapbox-gl-js/pull/9028

With this change, much more of the world is rendered, but the behavior does not exactly match what's possible on mapbox.js + Leaflet, in part due to the limitations @ryanhamley outlined [here](https://github.com/mapbox/mapbox-gl-js/issues/3055#issuecomment-554152535). I've pasted a few visual examples below.

### Questions:
- Would you consider this change to solve enough of your use case such that you don't feel the need to implement additional workarounds?
- If not, would you still consider this change to be an improvement from the current behavior?

### Examples:

With https://github.com/mapbox/mapbox-gl-js/pull/9028, the amount of the world that's shown depends on the aspect ratio of the viewport in containers <512px. Even when zoomed out all the way, the map will still fill the vertical space of the container. For example:
 
![Screen Shot 2019-11-26 at 3 03 43 PM](assets/mapbox__mapbox-gl-js-9028/004.png)

![image](assets/mapbox__mapbox-gl-js-9028/005.png)

This would be instead of the following behavior, which was originally requested above:

![Screen Shot 2019-04-10 at 7 24 16 PM](assets/mapbox__mapbox-gl-js-9028/002.png)