OK. There have been some comments/questions re: PR18282.

a) my PR is missing that PR, seems we just missed each other.

b) when using my patch I took a suggestion from issue39460 to test again:

root@x065:[/home/python/python3-3.9]./python -m test -v test_zipfile -m test_add_file_after_2107 --tempdir /tmp
== CPython 3.9.0a3+ (heads/bpo-39502-dirty:c54fe56362, Jan 30 2020, 15:52:37) [C]
== AIX-3-00C291F54C00-powerpc-64bit big-endian
== cwd: /tmp/test_python_303120
== CPU count: 4
== encodings: locale=ISO8859-1, FS=iso8859-1
0:00:00 Run tests sequentially
0:00:00 [1/1] test_zipfile
test_add_file_after_2107 (test.test_zipfile.StoredTestsWithSourceFile) ... ok

----------------------------------------------------------------------

Ran 1 test in 0.257s

OK

== Tests result: SUCCESS ==

1 test OK.

Total duration: 653 ms
Tests result: SUCCESS

Without the --tempdir setting it "skips" to PASS:

root@x065:[/home/python/python3-3.9]./python -m test -v test_zipfile -m test_add_file_after_2107
== CPython 3.9.0a3+ (heads/bpo-39502-dirty:c54fe56362, Jan 30 2020, 15:52:37) [C]
== AIX-3-00C291F54C00-powerpc-64bit big-endian
== cwd: /data/prj/python/python3-3.9/build/test_python_364784
== CPU count: 4
== encodings: locale=ISO8859-1, FS=iso8859-1
0:00:00 Run tests sequentially
0:00:00 [1/1] test_zipfile
test_add_file_after_2107 (test.test_zipfile.StoredTestsWithSourceFile) ... skipped 'Linux VFS/XFS kernel bug detected: mtime_ns=91301504000000000'

----------------------------------------------------------------------

Ran 1 test in 0.010s

OK (skipped=1)

== Tests result: SUCCESS ==

1 test OK.

Total duration: 252 ms
Tests result: SUCCESS

FYI