bpo-44895: Temporarily add an extra gc.collect() call (GH-27746)

bpo-44895: Temporarily add an extra gc.collect() call (GH-27746)

This is part of an investigation of a non-deterministic reference leak. While we're looking for the root cause, this is included temporarily so that CI doesn't fail on this particular issue. This enables it to find other regressions in the meantime, which would otherwise be shadowed by our known issue.
(cherry picked from commit 7bf28cbb4bf37fa6bdfc2d3f8a3939066b3f8f22)

Co-authored-by: Irit Katriel <1055913+iritkatriel@users.noreply.github.com>