This .t file was failing for me when running run-tests.py with python3.11. Then
I tried to run it with python3.10 and it failed anyway, even though it's the
default python3 interpreter. But with `python3 ./run-tests.py` it worked fine.

And this is what I found while looking at the way pygments lexer checks if a
file without extension is likely to be a python script:

  shebang_matches(text, r'pythonw?(3(\.\d)?)?')

Take guess why it doesn't work for python >= 3.10.

To work around this issue, we can simply hardcode an "easier" shebang for
pygments. This path to python interpreter obviously doesn't need to be
accurate, since we're not running this script.