Cherry-picked from #84838. I've tested it on NixOS 19.09 but not on 20.03, so I've left the checkboxes for building and testing below unchecked (brand new to NixOS, not sure if I'm doing it right?!).

Motivation for this change

The current version of tor-browser-bundle-bin is out-of-date, has known security vulnerabilities and is no longer available for download.

Things done

Updated tor-browser-bundle-bin from 9.0.7 to 9.0.9:

• Security fixes:
  • https://www.mozilla.org/en-US/security/advisories/mfsa2020-13/
  • https://www.mozilla.org/en-US/security/advisories/mfsa2020-11/
• Full changelog:
  • https://blog.torproject.org/new-release-tor-browser-909
  • https://blog.torproject.org/new-release-tor-browser-908

• 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.

Thanks!