Circles at extreme latitudes are not clamped but mirrored, and sometimes omitted

Nobody has claimed this yet.

**mapbox-gl-js version**:
0.53.0
**browser**:
Chrome
### Steps to Trigger Behavior

1. Add a source with points of latitude < -85.05 , or > 90
2. Style source with circle layer

### Link to Demonstration
https://jsfiddle.net/83m0L5hn/1/

This demo renders points at longitudes from 0 to 240, at intervals of 10. Red points have latitudes equal to longitude, and blue points have latitudes negative of longitude.

### Expected Behavior
Circles render properly at up til latitudes +/- 85.05, at which point they get clamped at that value.

### Actual Behavior
Circles past +/-90 latitude start approaching the equator again, as if mirroring from the top and bottom edges of the projection. In addition, extreme southerly points are omitted entirely (missing blue dot at very bottom)

cc/ @ryanhamley @mourner

Start by reproducing the behavior with the linked JSFiddle in Chrome using mapbox-gl-js 0.53.0. Trace how circle layers handle points beyond ±85.05 latitude, then verify that extreme points are clamped rather than mirrored or omitted and that the reproduction renders as expected.

Written by the indexing model from the issue text.