treewide: jdk: make it point to latest version

[doronbehar]

Motivation for this change

I want to encourage contributors to use (or at least try to use) the latest openjdk when they add new derivations that need Java. This change strives to make jdk point to the latest jdk, while every other derivation that uses jdk without an explicit version suffix, now uses jdk8 explicitly.

I'm still waiting for ofborg to tag this PR as "10.rebuild-linux: 0", that's why it's a draft.

See also https://discourse.nixos.org/t/nixpkgs-policy-regarding-libraries-available-in-multiple-versions/7026 .

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 nixpkgs-review --run "nixpkgs-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.

[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/nixpkgs-policy-regarding-libraries-available-in-multiple-versions/7026/4

[doronbehar]

I'm thinking that perhaps, it'll be better to make jdk point to the latest openjdk, but write a script that will make every derivation that has jdk in it's arguments, use jdk8 explicitly. This way, the PR will be tagged as 0: rebuild-linux and so it'll be still easy enough to merge this.

[doronbehar]

Closed in favor of #89731 .