[3.13] gh-133982: Use implementation-specific `open` in `test_fileio.OtherFileTests` (GH-135364) (GH-136149)

gh-133982: Use implementation-specific `open` in `test_fileio.OtherFileTests` (GH-135364)
(cherry picked from commit 23caccf74ce2c8dc5d9c5eb6350d21ef20c6ea0b)

Co-authored-by: Cody Maloney <cmaloney@users.noreply.github.com>