Motivation for this change

Fixes #72832

#65247 changed from using lndir to a plain symlink to link the JRE into the JDK, which got rid of the need to manually symlink the cmm directory. Not using lndir was found to be problematic and reverted in #68442, but the cmm fix was not added back. This PR fixes that.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nix-review --run "nix-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

Notify maintainers

cc @edwtjo @NeQuissimus @andrei-ilyin-mh