Ensure proper vertex input masks are used in 2D compatibility renderer

[clayjohn]

Fixes: #88937

There were two problems:

1. We were using RS::ARRAY_FORMAT_VERTEX | RS::ARRAY_COLOR | RS::ARRAY_TEX_UV (i.e. 1 | 3 | 4 AKA 111) instead of RS::ARRAY_FORMAT_VERTEX | RS::ARRAY_FORMAT_COLOR | RS::ARRAY_FORMAT_TEX_UV AKA 11001
2. We weren't initializing vertex_input_mask to anything and it wasn't always set so we end up with situations where it contains garbage data

[akien-mga]

Thanks!