Fix French arch --help test to match current translation

The coreutils-l10n translation uses the infinitive 'Afficher' rather
than 'Affiche', causing the test to fail in CI.

Author: sylvestre

static/js/wasm-terminal.test.html

@@ -359,7 +359,7 @@ <h1>wasm-terminal unit tests</h1>
     T.locale = "fr-FR";
     const frHelp = await executeCommandLine("arch --help");
     assert("arch --help in French contains French text",
-      frHelp.includes("Affiche l'architecture de la machine"), true);
+      frHelp.includes("Afficher l'architecture de la machine"), true);
 
     T.locale = "en-US";