set an interim paint in style_layer

[mannnick24]

this is in place of pr #9574

when a StyleLayer is created its paint member is undefined untill recalculate is called. there are render scenarios where paint is accessed between construction and recalculate being called first time

see https://github.com/mapbox/ibm-cognos-collab/issues/154

Instead of checking whether paint is undefined in a layer when it is used, set an interim possiblyEvaluated value if there are any paint properties.

There is a very simple test for this

[mannnick24]

@asheemmamoowala there is a good use case and a fiddle on https://github.com/mapbox/ibm-cognos-collab/issues/153
this was closed when I added a check on the layer.paint member
this change seeks to prevent paint from ever being undefined, by setting a default value.
I'm adding a test that is really simple

[mannnick24]

@asheemmamoowala I'm working on the idea that the race is between:

1. style.js update
   which calls layer.recalculate - which in turn initialises the paint member with possibly evaluated properties
2. map.js _render possibly stemming from a zoom event, although it must be skipping the style update - so style isnt dirty?

This really happens for us because we have a dynamic map... users can change the data slot mapping, essentially choosing different data to visualise, our code then removes layers and adds new ones and waits for the map to tell us its loaded
there is an ititial zoom level and then zoom levels are reapplied after the map is loaded

I have not found a reliable fiddle for this yet

[mourner]

This looks good apart from two nits.

[mourner]

Nit: this is not a public issue so it shoudn't be included.

[mourner]

Nit: you can remove this if because there's the same condition above.

[karimnaaji]

Merged as ef0884e, will be part of v1.10.1. Thanks @mannnick24 !