Don't rely on __noChroot for corepkgs

This doesn't work anymore if the "strict" chroot mode is
enabled. Instead, add Nix's store path as a dependency. This ensures
that its closure is present in the chroot.

corepkgs/nar.nix

@@ -41,9 +41,8 @@ derivation {
   args = [ "-e" builder ];
   inherit storePath hashAlgo compressionType;
 
-  # Don't build in a chroot because Nix's dependencies may not be there.
-  __noChroot = true;
-
   # Remote machines may not have ${nixBinDir} or ${coreutils} in the same prefixes
   preferLocalBuild = true;
+
+  inherit chrootDeps;
 }