Disable tests on s390x
Disable tests on s390x

When tests are run in QEMU the job just times out

geofft/nix-rust,berkowski/nix,MarkusJais/nix-rust,berkowski/nix,nix-rust/nix,berkowski/nix,xd009642/nix,geofft/nix-rust,nix-rust/nix,Susurrus/nix,xd009642/nix,Susurrus/nix,xd009642/nix,asomers/nix,Susurrus/nix,carllerche/nix-rust,MarkusJais/nix-rust,geofft/nix-rust,carllerche/nix-rust,asomers/nix,carllerche/nix-rust,MarkusJais/nix-rust