tests: Add quickBuild to all VM tests

tests/nixos/functional/common.nix

@@ -8,11 +8,6 @@ let
 
 in
 {
-  imports = [
-    # Add the quickBuild attribute to the check package
-    ./quick-build.nix
-  ];
-
   # We rarely change the script in a way that benefits from type checking, so
   # we skip it to save time.
   skipTypeCheck = true;

tests/nixos/functional/quick-build.nix

@@ -1,47 +0,0 @@
-test@{ lib, extendModules, ... }:
-let
-  inherit (lib) mkOption types;
-in
-{
-  options = {
-    quickBuild = mkOption {
-      description = ''
-        Whether to perform a "quick" build of the Nix package to test.
-
-        When iterating on the functional tests, it's recommended to "set" this
-        to `true`, so that changes to the functional tests don't require any
-        recompilation of the package.
-        You can do so by buildin the `.quickBuild` attribute on the check package,
-        e.g:
-        ```console
-        nix build .#hydraJobs.functional_user.quickBuild
-        ```
-
-        We don't enable this by default to avoid the mostly unnecessary work of
-        performing an additional build of the package in cases where we build
-        the package normally anyway, such as in our pre-merge CI.
-      '';
-      type = types.bool;
-      default = false;
-    };
-  };
-
-  config = {
-    passthru.quickBuild = 
-      let withQuickBuild = extendModules { modules = [{ quickBuild = true; }]; };
-      in withQuickBuild.config.test;
-
-    defaults = { pkgs, ... }: {
-      config = lib.mkIf test.config.quickBuild {
-        nix.package = pkgs.nix_noTests;
-
-        system.forbiddenDependenciesRegexes = [
-          # This would indicate that the quickBuild feature is broken.
-          # It could happen if NixOS has a dependency on pkgs.nix instead of
-          # config.nix.package somewhere.
-          (builtins.unsafeDiscardStringContext pkgs.nix.outPath)
-        ];
-      };
-    };
-  };
-}