gh-90815: Fix test_embed for Windows PGO build with mimalloc (GH-94790)

Fixes the failure of PGO building with `mimalloc` on Windows, ensuring that `test_bpo20891` does not break profiling data (`python31*.pgc`).
(cherry picked from commit 4a6bb30eb600e3b18f4a84c1be922c07758c613f)

Co-authored-by: neonene <53406459+neonene@users.noreply.github.com>