ci/alpine: build Mesa on top of Alpine 3.16

Alpine is lightweight distribution with musl-libc. We currently testing with Debian and Fedora, which are both Glibc based distro, so this option should be able give us chance to catch more build-system and #ifdefs bugs.

Alpine image is a small ~ 200M (comparing to Fedora with ~ 400M) image. When most of the code is ccached, runtime is around ~ 2 minutes (including linking, which is done by system linker, not the Mold, which will be available after next Alpine version release).

Based on: !19587 (merged)