top-level/release-outpaths-parallel: rename from top-level/release-attrpaths-parallel

This file takes attrpaths as input and returns chunks of derivations,
aka a subset of release-outpaths - while release-attrpaths-superset
returns only an attrpath, not any derivations.

Thus, as a specialization of release-outpaths, the name
release-outpaths-parallel matches much better.

(cherry picked from commit 4ad7d21c88)

ci/eval/default.nix

@@ -98,7 +98,7 @@ let
         set +e
         command time -o "$outputDir/timestats/$myChunk" \
           -f "Chunk $myChunk on $system done [%MKB max resident, %Es elapsed] %C" \
-          nix-env -f "${nixpkgs}/pkgs/top-level/release-attrpaths-parallel.nix" \
+          nix-env -f "${nixpkgs}/pkgs/top-level/release-outpaths-parallel.nix" \
           --eval-system "$system" \
           --option restrict-eval true \
           --option allow-import-from-derivation false \