Potential IE 11 test fixes

This could fix these tests:
```
Renderer/Draw draws with culling. (show summary)
Renderer/Draw draws with front face winding order. (show summary)
Renderer/Draw draws with the depth test. (show summary)
Renderer/Draw draws with depth range. (show summary)
Renderer/Draw draws with stencil test (front). (show summary)
Renderer/Draw draws with stencil test (back). (show summary)
Scene/Scene constructor sets contextOptions. (show summary)
Widgets/CesiumWidget/CesiumWidget can set contextOptions. (show summary)
Widgets/Viewer/Viewer can set contextOptions. (show summary)
```

If any of the stencil ones still fail, let me know what IE 11 reports for `context.stencilBits`.  If the others still fail, `TRIANGLE_STRIP` is also not supported and I will add index data.

CC #1616