cameraForBounds should comply with map constrains

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**mapbox-gl-js version**: 1.9.1

**browser**: all

### Steps to Trigger Behavior

1. In full screen mode, use [`cameraForBounds`](https://www.mapbox.com/mapbox-gl-js/api#map#cameraforbounds) with the following:
```js
const center = [34.801497299999994, 32.082714300000006];
const bbox = [ center, center ];
const camera = this.map.cameraForBounds(bbox, { maxZoom: 1 });
```
2. Observe the new `camera.center` is `{lng: 34.801497299999994, lat: 32.082714300000006}`
2. `jumpTo` the new center:
```js
this.map.jumpTo({ center: camera.center });
```
3. Observe `map.getCenter()` is `{lng: 34.801497299999994, lat: 22.43134251570592}`
4. the `jumpTo` call initiate `transform._constrain()` but that is not reflected with the data from [`cameraForBounds`](https://www.mapbox.com/mapbox-gl-js/api#map#cameraforbounds)

My use-case is initiating `easeTo/flyTo/jumpTo` only if the center is different so i'm comparing the results of `cameraForBounds` with the current `map.getCenter()`. With the current flow a user cannot initiate map movement with preconditions.

### Link to Demonstration

https://jsfiddle.net/shayy/rs8f9qvx/5/embedded/result
Press `space` multiple times and watch the console logs.

Start at the cameraForBounds and jumpTo entry points, then trace how transform._constrain() affects map.getCenter(). Reproduce the jsfiddle case with a zero-area bounds value and maxZoom: 1; done means cameraForBounds and the subsequent map movement report the same constrained center.

Written by the indexing model from the issue text.