src/script/run-make.sh: clang 14->16

src/script/run-make.sh: clang 14->16

Currently our jammy ci (jenkins) builders are only able to
(apt) install clang 14 as the latest version available.

Clang stable is already at 19 today (i.e we're 5 major releases behind).
Meaning, full support of C++20 and some bugs [1] requiring us to update
the compiler used for make check.

As updating to Ubuntu 24 is not feasable in the near future and
containerized builds is not yet merged - with this patch, we
would get clang-16 directly form llvm installation script.

Note: discover_compiler() would prefer clang-16 even if
      clang-14 will be installed by apt in INSTALL_EXTRA_PACKAGES
      defined below.

[1] https://github.com/llvm/llvm-project/issues/52696

Signed-off-by: Matan Breizman <mbreizma@redhat.com>