Blender Git Loki

Fix T71461: Add IN_PLACE_INSTANCES to `part_prim` and `part_axis` object mode particle shaders

For `Particle Properties -> Viewport Display -> Display As` set to
circle/cross/axis, particle instances are associated with a single
resource handle (and, in particular, a single model matrix), so define
`IN_PLACE_INSTANCES` to get the right index for `ModelMatrix` and
`ModelInverseMatrix` in the shader.

Differential Revision: https://developer.blender.org/D6220