check-meta.nix: fix self-contradictory error messages

See https://github.com/NixOS/nixpkgs/pull/222792#pullrequestreview-1356114111

You can't just `lib.filter _ lib.systems.all` -- that throws away
important information, leading to nixpkgs disagreeing with itself
like this:

```
$ NIXPKGS_ALLOW_BROKEN=1 nix-instantiate . -A pkgsStatic.systemd
error: Package ‘systemd-252.5’ in ... is only supported on ... x86_64-linux but not on requested x86_64-linux, refusing to evaluate.
```

After:

```
$ NIXPKGS_ALLOW_BROKEN=1 nix-instantiate . -A pkgsStatic.systemd
error: Package ‘systemd-252.5’ in ... is not available on the requested hostPlatform:
         hostPlatform.config = "x86_64-unknown-linux-musl"
         package.meta.platforms = [
           "aarch64-linux"
           "armv5tel-linux"
           "armv6l-linux"
           "armv7a-linux"
           "armv7l-linux"
           "i686-linux"
           "m68k-linux"
           "microblaze-linux"
           "microblazeel-linux"
           "mipsel-linux"
           "mips64el-linux"
           "powerpc64-linux"
           "powerpc64le-linux"
           "riscv32-linux"
           "riscv64-linux"
           "s390-linux"
           "s390x-linux"
           "x86_64-linux"
         ]
         package.meta.badPlatforms = [
           {
             isStatic = true;
             parsed = { };
           }
         ]
       , refusing to evaluate.
```

0 files changed, 0 insertions, 0 deletions