Blender Git Loki

Fix T73941: Custom normals from normal edit modifier ignored by further modifiers.

This commit actually fixes several issues in this modifier, but main one
from the report was caused by adding a `CD_NORMAL` layer to loops to
store temp real clnors. Unless we plan on modifying the topology itself,
this is useless, and would require some additional 'dirty normals'
tagging to work properly, so just switched to simpler, cleaner solution
of having a local array of computed clnors.