Enhance custom framebuffer binding state to allow
specification of clear color as part of the loadstore
state at framebuffer bind time.
This ensures all parameters controlling attachment
loading and storage behaviour can be explicitly
specified when binding a framebuffer.
This change enables optimizations which leverage
explicit framebuffer load store state to also specify
a clear color without prematurely triggering a
clear which may occur independently to
render work when using GPU_framebuffer_clear(..).
Authored by Apple: Michael Parkin-White.
Pull Request: https://projects.blender.org/blender/blender/pulls/111810
503bdbf777