stdenv: check if this fixes laziness issue

```
error: cannot coerce null to a string

at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/ofborg-evaluator-3/pkgs/development/coq-modules/coq-lsp/default.nix:34:60:

    33|     homepage = "https://github.com/ejgallego/coq-lsp";
    34|     changelog = "https://github.com/ejgallego/coq-lsp/blob/${defaultVersion}/CHANGES.md";
```

pkgs/stdenv/generic/check-meta.nix

@@ -390,7 +390,7 @@ let
  # -----
  else { valid = "yes"; });
 
- assertValidity = { attrs, pos ? null, references ? [] }: let
+ commonMeta = { validity, attrs, pos ? null, references ? [] }: let
  outputs = attrs.outputs or [ "out" ];
 
  # The meta attribute is passed in the resulting attribute set,
@@ -431,7 +431,9 @@ let
  then lib.all (d: d.meta.available or true) references
  else true);
  };
+ in meta;
 
+ assertValidity = { meta, attrs }: let
  validity = checkValidity attrs;
  in validity // {
  # Throw an error if trying to evaluate a non-valid derivation
@@ -443,7 +445,6 @@ let
  yes = true;
  }.${validity.valid};
 
- inherit meta;
  };
 
-in assertValidity
+in { inherit assertValidity commonMeta; }

pkgs/stdenv/generic/make-derivation.nix

@@ -501,7 +501,8 @@ else let
  lib.mapNullable unsafeDerivationToUntrackedOutpath attrs.allowedRequisites;
  };
 
- validity = checkMeta { inherit attrs pos references; };
+ validity = let meta = checkMeta.commonMeta { inherit validity attrs pos references; }; in
+ (checkMeta.assertValidity { inherit meta attrs; }) // { inherit meta; };
 
  checkedEnv =
  let