Tests: increase timeout in expect

This command takes 7 seconds on nix 2.22, but only 0.5 seconds on nix
2.20.

    NIX_PATH=nixpkgs=channel:nixos-23.05 nix-shell -p --run :

tests/t16-shopt.sh

@@ -9,7 +9,7 @@ check "Options are the same" diff tmp/nix-shell tmp/cached-nix-shell
 rm tmp/nix-shell tmp/cached-nix-shell
 
 run $(nix-shell --pure -p which expect --run 'which expect') << 'EOF'
-set timeout 5
+set timeout 60
 log_user 0
 
 spawn nix-shell --pure -p