imm32: When updating a NULL HIMCC with NULL just return NULL. Handle the NULL HIMCC for the compstr when doing a ImmNotifyIME for a reset.

wined3d: SFLAG_INTEXTURE is the same as SFLAG_INDRAWABLE for offscreen render targets when ORM_FBO is used.

wined3d: Move binding the texture and dirtifying the sampler to its own function from surface_download_data().