dotnet: add darwin.ICU dependency to AOT test

This dependency seems to have been removed accidentally along with the
framework dependencies in #398707, so the test has been broken since
then.

Fixes: dd0f03a56cf2be99f0904ff1f64e1cc5fb201d43

pkgs/development/compilers/dotnet/wrapper.nix

@@ -6,6 +6,7 @@
   testers,
   runCommand,
   runCommandWith,
+  darwin,
   expect,
   curl,
   installShellFiles,
@@ -223,6 +224,7 @@ stdenvNoCC.mkDerivation (finalAttrs: {
                 ]
                 ++ lib.optional stdenv.hostPlatform.isDarwin [
                   swiftPackages.swift
+                  darwin.ICU
                 ];
               build = ''
                 dotnet restore -p:PublishAot=true