lib/tests: avoid full rebuild when only maintainers change

The vast majority of CI jobs to build the lib tests are caused by
changes in the maintainer list. In this case, we currently run the full
test-suite which takes 3-4 minutes. By moving the maintainers and teams
tests out of the test-with-nix file, we save almost all of that.
Building only those two tests on a change is almost instant. This only
works, because we previously enabled cachix for the workflow.

Note, that these tests are not actually run with both nix versions, even
though they were listed in the "test with specific nix version" file.
That's because we only differ in the nix version run *inside* the
sandbox, but not doing the outer build.

Since this file seems to be re-used by NixOS/nix' CI, this is
technically a small loss in coverage for that repo, but nixpkgs CI
considerations outweigh that. But because of this, I left the other
non-nix-version-specific tests in that file.

(cherry picked from commit a7f4e0f9ae)
(cherry picked from commit af25d1ce8c)

lib/tests/maintainers.nix

@@ -54,7 +54,7 @@ let
 
   missingGithubIds = lib.concatLists (lib.mapAttrsToList checkMaintainer lib.maintainers);
 
-  success = pkgs.runCommand "checked-maintainers-success" { } ">$out";
+  success = pkgs.runCommand "checked-maintainers-success" { } "mkdir $out";
 
   failure =
     pkgs.runCommand "checked-maintainers-failure"

lib/tests/release.nix

@@ -20,5 +20,14 @@ let
 in
 pkgs.symlinkJoin {
   name = "nixpkgs-lib-tests";
-  paths = map testWithNix nixVersions;
+  paths = map testWithNix nixVersions ++ [
+    (import ./maintainers.nix {
+      inherit pkgs;
+      lib = import ../.;
+    })
+    (import ./teams.nix {
+      inherit pkgs;
+      lib = import ../.;
+    })
+  ];
 }

lib/tests/test-with-nix.nix

@@ -19,14 +19,6 @@ pkgs.runCommand "nixpkgs-lib-tests-nix-${nix.version}"
     buildInputs = [
       (import ./check-eval.nix)
       (import ./fetchers.nix)
-      (import ./maintainers.nix {
-        inherit pkgs;
-        lib = import ../.;
-      })
-      (import ./teams.nix {
-        inherit pkgs;
-        lib = import ../.;
-      })
       (import ../path/tests {
         inherit pkgs;
       })