Targets that don't support tail calls will see:
/home/ci/zig/.zig-cache/o/35dbe82c8e4d49ae5b7d630329568133/tmp.zig:5:5: error: unable to perform tail call: compiler backend 'stage2_llvm' does not support tail calls on target architecture 'powerpc64le' with the selected CPU feature flags
So just run this test on a known-good target.
backend=auto (now the default if backend is omitted) means to let the compiler
pick whatever backend it wants as the default. This is important for platforms
where we don't yet have a self-hosted backend, such as loongarch64.
Also purge a bunch of redundant target=native.
Currently, the compiler (like @typeName) writes it `fn(...) Type` but
zig fmt writes it `fn (...) Type` (notice the space after `fn`).
This inconsistency is now resolved and function types are consistently
written the zig fmt way. Before this there were more `fn (...) Type`
occurrences than `fn(...) Type` already.
Alex Rønne Petersen