Test: libcrmcommon: Use g_assert_*() instead of g_assert()

"...Similarly, it [g_assert()] must not be used in unit tests, otherwise
the unit tests will be ineffective if compiled with G_DISABLE_ASSERT.
Use g_assert_true() and related macros in unit tests instead."

https://developer.gnome.org/glib/unstable/glib-Testing.html#g-assert

Also remove redundant test for pcmk__str_any_of().

Signed-off-by: Reid Wahl <nrwahl@protonmail.com>