Drop/Update old shell-based tests
The following two files used to be unit tests before we transitioned to Meson, but were not fully ported to the Meson test framework when we transitioned. The C parts of them are (incorrectly) run as standalone unit tests, ignoring the fact that they were designed to have a shell wrapper to feed them with data and check their output.
Update them, ideally to make them entirely C based and drop the shell.
tests/run-assert-msg-test.sh
tests/run-collate-tests.sh
In addition, the following shell scripts are old and can probably be dropped:
check-abis.sh
gio/tests/x-content/unix-software/autorun.sh
glib/libcharset/make-patch.sh
glib/libcharset/update.sh
glib/update-pcre/update.sh