There may well be more vertex shaders that need this, but I couldn't find them
in my testing.
Differential Revision: https://developer.blender.org/D4921
Apply clang format as proposed in T53211.
For details on usage and instructions for migrating branches
without conflicts, see:
https://wiki.blender.org/wiki/Tools/ClangFormat
Shaded triangles are not yet implemented (request from gpumaterials).
This also changes the mechanism to draw curve normals to make it not
dependant on normal size display. This way different viewport can
reuse the same batch.