Disable flaky unit test on OSX (#4379) #6755

Job	Run time
CodeQL analysis	3m 35s
Code health check	1m 11s
Build doc	5m 50s
pyca/cryptography test	29s
Type hints check	30s
Check SPDX identifiers	7s
ubuntu-latest 3.7 non_root -K scanner	3m 38s
ubuntu-latest 3.8 non_root -K scanner	3m 48s
ubuntu-latest 3.9 non_root -K scanner	4m 20s
ubuntu-latest 3.10 non_root -K scanner	3m 37s
ubuntu-latest 3.11 non_root -K scanner	3m 39s
ubuntu-latest 3.12 non_root -K scanner	5m 18s
ubuntu-latest 3.12 root -K scanner	5m 0s
ubuntu-latest pypy3.9 root -K scanner	5m 18s
ubuntu-latest libpcap 3.12 root -K scanner	4m 54s
macos-12 3.12 both -K scanner	6m 1s
ubuntu-latest 3.12 root -k scanner	3m 55s
ubuntu-latest pypy3.9 root -k scanner	5m 18s
macos-12 3.12 both -k scanner	2m 44s
	1h 9m 12s

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