buildRustPackage: factor out check phase to cargoCheckHook

API change:

`cargoParallelTestThreads` suggests that this attribute sets the
number of threads used during tests, while it is actually a boolean
option (use 1 thread or NIX_BUILD_CORES threads). In the hook, this
is replaced by a more canonical name `dontUseCargoParallelTests`.

pkgs/development/tools/the-way/default.nix

@@ -17,7 +17,7 @@ rustPlatform.buildRustPackage rec {
 
   cargoSha256 = "sha256-jTZso61Lyt6jprBxBAhvchgOsgM9y1qBleTxUx1jCnE=";
   checkFlagsArray = lib.optionals stdenv.isDarwin [ "--skip=copy" ];
-  cargoParallelTestThreads = false;
+  dontUseCargoParallelTests = true;
 
   postInstall = ''
     $out/bin/the-way config default tmp.toml