This is a stepping stone in converting more pairs of ``char*`` and ``size_t`` to ``zend_string*`` across the CLI SAPI.
Also amend the CLI SAPI test setup to output it's content when it crashes/errors so that one can debug ASAN/UBSAN/MSAN violations.
Drive-by MSAN fix.
Co-authored-by: Arnaud Le Blanc <arnaud.lb@gmail.com>