Motivation for this change

One libuv test fails more often than not on my ARMv7 machine. I filed an upstream ticket, but it's not clear what the problem is, and it doesn't seem upstream is going to look at it. Since nobody else is complaining about this, I am assuming it is limited only to ARMv7, and have restricted the change to this arch. I also see that many tests are already disabled in libuv for spurious failures, so I'm hoping a change like this isn't too controversial.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• 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 nox --run "nox-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)
• Fits CONTRIBUTING.md.