Use the commit as the testing ref for render.py
This MR modifies the render.py script to use the commit sha as the testing reference, not the branch from which it came, as the branch doesn't seem to get fetched during CI jobs any more.
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This MR modifies the render.py script to use the commit sha as the testing reference, not the branch from which it came, as the branch doesn't seem to get fetched during CI jobs any more.