ebdae75736
`MeshBufferCache` is a struct representing a list of buffers. As such, `GPUIndexBuf **tris_per_mat` is out of place as it does not represent one of the buffers in the list. In fact this member should be close to `GPUBatch **surface_per_mat` as they are related. The code for dependencies between buffer and batch had to be reworked as it relies on the member's position. Differential Revision: https://developer.blender.org/D12227