The "cuda_mem_map_mutex" was potentially being locked recursively during the call to "CUDADevice::move_textures_to_host", which crashed. This moves around the locking and unlocking of "cuda_mem_map_mutex", so that it doesn't call a function that locks it while still holding the lock. Reviewed By: pmoursnv Maniphest Tasks: T85089, T84734 Differential Revision: https://developer.blender.org/D10219