Make processPythonExecution return a future (#57855)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/57855
We already had a helper to run Python functions, which was nice (it de-duplicated some code). This helper was however taking a callback which, as I said, isn't as nice as it returning a Future. Hence here I change this.
ghstack-source-id: 129567054
Test Plan: CI
Reviewed By: mrshenli
Differential Revision: D28253846
fbshipit-source-id: d854d4aa163798fb015cd6d46932f9ff1d18262e
