Revert "stdenv: Store one package per line in nix-support/propagated-*"

As @oxij points out in [1], this breakage is especially serious because
it changes the contents of built environments without a corresonding
change in their hashes. Also, the revert is easier than I thought.

This reverts commit 3cb745d5a6.

[1]: https://github.com/NixOS/nixpkgs/pull/27427#issuecomment-317293040

pkgs/development/haskell-modules/generic-builder.nix

@@ -311,7 +311,7 @@ stdenv.mkDerivation ({
     ${optionalString isGhcjs ''
       for exeDir in "$out/bin/"*.jsexe; do
         exe="''${exeDir%.jsexe}"
-        printLines '#!${nodejs}/bin/node' > "$exe"
+        printf '%s\n' '#!${nodejs}/bin/node' > "$exe"
         cat "$exeDir/all.js" >> "$exe"
         chmod +x "$exe"
       done