Split multi-material meshes into multiple meshes with one material each.
Split multi-material meshes into multiple meshes with one material each.

Previously the same material was used for the whole mesh (causing
problems, for example, in Sponza).

GPUOpen-LibrariesAndSDKs/RadeonProRender-Baikal,GPUOpen-LibrariesAndSDKs/RadeonProRender-Baikal,GPUOpen-LibrariesAndSDKs/RadeonProRender-Baikal