cuda-modules: fix `sort` predicate stability (#368366)

pkgs/development/cuda-modules/generic-builders/multiplex.nix

···
   redistArch = flags.getRedistArch hostPlatform.system;
 
   preferable =
-    p1: p2: (isSupported p2 -> isSupported p1) && (strings.versionAtLeast p1.version p2.version);
+    p1: p2: (isSupported p2 -> isSupported p1) && (strings.versionOlder p2.version p1.version);
 
   # All the supported packages we can build for our platform.
   # perSystemReleases :: List Package

pkgs/development/python-modules/torch/source/default.nix

···
     ''
     + lib.optionalString (cudaSupport && cudaPackages ? cudnn) ''
       export CUDNN_INCLUDE_DIR=${lib.getLib cudnn}/include
-      export CUDNN_LIB_DIR=${cudnn.lib}/lib
+      export CUDNN_LIB_DIR=${lib.getLib cudnn}/lib
     ''
     + lib.optionalString rocmSupport ''
       export ROCM_PATH=${rocmtoolkit_joined}