rust: Remove use of `py.eval()`...
rust: Remove use of `py.eval()`
The previous Rust code allocated an intermediate `Vec`, converted that
to a Python list, then used `eval` to run Python code that converts that
list to a Python set.
rust-cpython exposes Rust bindings for Python sets, let’s use that instead
to construct a set directly.
Differential Revision:
https://phab.mercurial-scm.org/D10328
