Remove RUN_FLAKY_TESTS requirements for a few tests.

[rodrigc]

Unicode fixes for Python 3 have fixed these tests on Python 2.

Fixes: #3339

[mention-bot]

@rodrigc, thanks for your PR! By analyzing the history of the files in this pull request, we identified @djmitche, @tardyp and @bukzor to be potential reviewers.

[tardyp]

@rodrigc #3339 is not about u'xx' vs 'xx' it is about

log:stdio (0)\n

vs

log:stdio (29)

but there have been changes since on the log system, and maybe this is more reliable (notably there is no more a timing when compressing logs where the log line count comes to zero)