The ctypes tests all seem to be protected with code that checks for None, and explicitly skip the test in that case. The skip message should be visible when you run the test in verbose mode.

We could avoid skipping these tests in 2.7 by adding a special case for AIX that loads the library via CDLL("libc.a(shr[_64].o)", RTLD_MEMBER). Like an extension of the special cases already at <https://hg.python.org/cpython/file/v2.7.12/Lib/ctypes/test/test_loading.py#l8>, but we have to set the RTLD_ flag as well as the library name.