Re: [PATCH v2 8/8] u-string-list: move "remove duplicates" test to "u-string-list.c"

> We use "test-tool string-list remove_duplicates" to test the
> "string_list_remove_duplicates" function. As we have introduced the unit
> test, we'd better remove the logic from shell script to C program to
> improve test speed and readability.
> 
> As all the tests in shell script are removed, let's just delete the
> "t0063-string-list.sh" and update the "meson.build" file to align with
> this change.
> 
> Also we could simply remove "DISABLE_SIGN_COMPARE_WARNINGS" due to we
> have already deleted related code.