floorp: Fix tests for floorp-bin change

Several of the `floorp` tests were broken by the upstream switch to
`floorp-bin`. Most changes were to do with not being able to use
`programs.floorp.wrappedPackageName` in expected results.

tests/modules/programs/firefox/setup-firefox-mock-overlay.nix

@@ -25,6 +25,7 @@ in
           binaryName = cfg.wrappedPackageName;
           gtk3 = null;
           meta.description = "I pretend to be ${cfg.name}";
+          meta.mainProgram = lib.toLower cfg.name;
         };
         outPath = null;
         buildScript =