nixos/lib/testing: remove alias usage

[SuperSandro2000]

Before I got this error:

 ➜ command nix-build -A nixosTests.portunus
error:
       … while evaluating the attribute 'drvPath'
         at /home/user/src/nixpkgs/lib/customisation.nix:365:7:
          364|     in commonAttrs // {
          365|       drvPath = assert condition; drv.drvPath;
             |       ^
          366|       outPath = assert condition; drv.outPath;

       … while calling the 'derivationStrict' builtin
         at <nix/derivation-internal.nix>:34:12:
           33|
           34|   strict = derivationStrict drvAttrs;
             |            ^
           35|

       … while evaluating the module argument `pkgs' in "/home/user/src/nixpkgs/nixos/modules/services/hardware/bluetooth.nix":

       … while evaluating the option `nodes.machine.nixpkgs.localSystem':

       … while evaluating the option `nodes.machine.nixpkgs.system':

       … while evaluating definitions from `/home/user/src/nixpkgs/nixos/lib/testing/nodes.nix':

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: attribute 'hostPlatform' missing
       at /home/user/src/nixpkgs/nixos/lib/testing/nodes.nix:16:22:
           15|
           16|   inherit (hostPkgs) hostPlatform;
             |                      ^
           17|
       Did you mean rustPlatform?

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 24.11 Release Notes (or backporting 23.11 and 24.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

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[amarshall]

Had this issue, verified fixes it in my config.