New review comment by classabbyamp on void-packages repository

https://github.com/void-linux/void-packages/pull/39972#discussion_r996355070

Comment:
let's use a case statement here instead because, while we don't currently have i686-musl, we should still consider it

and also change the `ci-skip` to `no` because it fails locally too

```suggestion
case "$XBPS_TARGET_MACHINE" in
	i686*)
		make_check=no # Tests fail to build on i686 with error "ran out of registers during register allocation"
		;;
esac
```

and, as a stylistic thing, let's put this before the functions and after the main variable block