t/unit-tests: update clar to fcbed04

t/unit-tests: update clar to fcbed04

Update clar to fcbed04 (Merge pull request #123 from
pks-gitlab/pks-sandbox-ubsan, 2025-09-10). The most significant changes
since the last version include:

  - Fixed platform support for HP-UX.

  - Fixes for how clar handles the `-q` flag.

  - A couple of leak fixes for reported clar errors.

  - A new `cl_invoke()` function that retains line information.

  - New infrastructure to create temporary directories.

  - Improved printing of error messages so that all lines are now
    properly indented.

  - Proper selftests for the clar.

Most of these changes are somewhat irrelevant to us, but neither do we
have to adjust to any of these changes, either. What _is_ interesting to
us though is especially the fixed support for HP-UX, and eventually we
may also want to use `cl_invoke()`.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>