We have some testcases that assert that type modules are unloaded after
the last reference on them is dropped. Comment out those asserts now
that we turned the last unref into a no-op.
https://bugzilla.gnome.org/show_bug.cgi?id=693351
Very many testcases, some GLib tools (resource compiler, etc) and
GApplication were calling g_type_init().
Remove those uses, as they are no longer required.
https://bugzilla.gnome.org/show_bug.cgi?id=686161