The test also fails on PPC64 Fedora 3.x:
https://buildbot.python.org/all/#/builders/237/builds/40

The test pass on PPC64 Fedora 3.8, the latest build still used "LANG=en_US.UTF-8":
https://buildbot.python.org/all/#/builders/163/builds/12

The test still passed on PPC64 Fedora 3.9 in build 15 which was using LANG=en_US.UTF-8:
https://buildbot.python.org/all/#/builders/34/builds/15

pythoninfo:

pre_config[utf8_mode]: 0
os.environ[LANG]: en_US.UTF-8
sys.flags: sys.flags(debug=0, inspect=0, interactive=0, optimize=0, dont_write_bytecode=0, no_user_site=0, no_site=0, ignore_environment=0, verbose=0, bytes_warning=0, quiet=0, hash_randomization=1, isolated=0, dev_mode=False, utf8_mode=0)
sys.filesystem_encoding: utf-8/surrogateescape


So the test started to fail when the buildbot worker configured changed to use LANG=C.UTF-8.