Message 411050 - Python tracker

Another measure using the command:

    PYTHONHASHSEED=0 ./python -X showrefcount -c pass

I had to run the command 20 times to get a stable value, I don't know why.

main branch: [21981 refs, 5716 blocks]
PR: [21887 refs, 5667 blocks]

=> the PR removes 94 references and 49 memory blocks.