test_matmul_tiled is never executed

[navalnica]

Q5 has following line that runs local tests: !python3 -m pytest -v -k "matmul and cpu".

However this doesn't run test_matmul_tiled test.
To run this test one must add another notebook cell with command !python3 -m pytest -v -k "matmul_tiled"

I guess it's better to update existing line with the following !python3 -m pytest -v -k "matmul and cpu or matmul_tiled"