* CMakeLists: pass `-Dstrip` for release zig builds
* pass -target and -mcpu to zig1. works around llvm on freebsd
incorrectly detecting "freestanding" instead of "freebsd" for the
native OS.
* ci.ziglang.org is now responsible for creating aarch64-macos tarballs
rather than Azure.
Empirically, the ReleaseSmall std lib tsets take about 55 minutes on the
CI, and is the bottleneck causing timeouts. So this commit disables full
coverage in favor of running a smaller set of ReleaseSmall std lib tests.
