Cryptomatte passes would generate a feathered outline
in Metal due to missing texture fence in chained
read->modify->write->read->... patterns.
Added imageFence function to explicitly state that
imageStore's should be visible to future imageLoad's.
Authored by Apple: Michael Parkin-White
Pull Request: https://projects.blender.org/blender/blender/pulls/119163
6b56ed3cd3