ignore-intermittent.txt: add tests/tail/retry

[oech3]

#12059 (comment)

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/cut/bounded-memory (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/pr/bounded-memory (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/tail/tail-n0f (passes in this run but fails in the 'main' branch)
Congrats! The gnu test tests/csplit/csplit-heap is now passing!
Note: The gnu test tests/env/env-signal-handler was skipped on 'main' but is now failing.

[cakebaker]

Thanks!