haskell-split: disable test suite to avoid transient build failures

We have frequent build failures of "split" because the QuickCheck testsuite
cannot generate enough conclusive test cases, i.e. in

https://hydra.nixos.org/build/34857780/nixlog/1/raw

Cc: @byorgey

pkgs/development/haskell-modules/configuration-common.nix

···
   # tinc is a new build driver a la Stack that's not yet available from Hackage.
   tinc = self.callPackage ../tools/haskell/tinc {};
 
+  # Avoid transient build failures because the QuickCheck testsuite cannot
+  # generate enough conclusive test cases.
+  split = dontCheck super.split;
+
 }