Extract a mask from the stencil buffer and use that texture instead
when texture views are not available.
Needed for supporting the Windows ARM software driver.
The workaround is isolated on its own class so it's easy to remove once
it's no longer needed.
Note that while this adds a function to check if texture views are available
(`GPU_texture_view_support`), at the moment this always returns true in
practice, since OpenGL 4.3 is the minimum supported version.
A separate patch will be needed to allow Blender to run using
OpenGL 4.2 + extensions.
Pull Request: https://projects.blender.org/blender/blender/pulls/111402
Miguel Pozo
f63a0e670a