Blender Git Loki

OpenGL: early exit from functions that don't mix with core profile

These parts will not be part of final viewport, but are called indirectly during the transition. To avoid runtime errors on core profile, exit early -- functions effectively do nothing.

I put the early exits inside the functions to avoid cluttering the code that calls these. But (long term) the calling functions need to change.

Basic shader's detect_options function was unused and full of old, so I deleted it.

Part of T51164