Blocks with no models now appear incorrect

Relates to MC-153547.

If a block has an invalid model, it no longer uses the checkerboard texture - it instead appears as a random part of the blocks atlas, incorrectly stretched out. This clearly should not happen and looks wrong without being clear that there is an error.

Only blocks placed in the world appear to be affected - items with broken models still correctly appear as a checkered cube.

Expected result would be for placed blocks to have the correct “error” appearence - either black and magenta as they were previously, or perhaps a new, dedicated error checkerboard to distinguish “model issues” from “texture issues” (e.g. black and red? example attached).