Previously, we were assuming that `which <python>` return the path to
the python executable. This is not true when using pyenv shims, which
are bash scripts. Instead, we have to use `sys.executable`. Luckily,
we're already querying the python interpreter and can do it in that
pass.
We are also not allowed to cache the execution of the python interpreter
through the shim because pyenv might change the target. As a heuristic,
we check whether `sys.executable`, the real binary, is the same our
canonicalized `which` result.
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Co-authored-by: Zanie Blue <contact@zanie.dev>
