Various tests in the lit testing suite expect specific return codes and forms of diagnostic message from utility programs. As per POSIX.1-2017 XCU Section 1.4, Utility Description Defaults, "[the] format of diagnostic messages for most utilities is unspecified". The STDERR subsections of the cat and wc utilities merely indicate that "[the] standard error shall be used only for diagnostic messages". The corresponding EXIT STATUS subsections merely indicate, with regard to errors, an exit value of >0.
The affected tests are updated to accept the applicable diagnostic message as produced by the utilities on AIX. The exit value is normalized using not as necessary.