Speedup IMB_rotate_orthogonal (used for example in auto-rotating
videos that were shot sideways on a phone) by: 1) not copying previous
pixel values into new result, only for them to be immediately
overwritten by rotated pixels, and 2) using multi-threading.
Performing rotation of 1920x1080 resolution HDR (float) video frame
goes from 20ms down to 5ms (Ryzen 5950X, Windows)
Pull Request: https://projects.blender.org/blender/blender/pulls/135158
525ece8465