test: improve lib/readline.js coverage

PR-URL: #42686
Refs: https://coverage.nodejs.org/coverage-a0461255c05c79cf/lib/readline.js.html#L105
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Moshe Atlow <[email protected]>

Author: fossamagna

test/parallel/test-readline-interface.js

@@ -71,6 +71,19 @@ function assertCursorRowsAndCols(rli, rows, cols) {
   assert(rl instanceof readline.Interface);
 }
 
+{
+  const fi = new FakeInput();
+  const rli = new readline.Interface(
+    fi,
+    fi,
+    common.mustCall((line) => [[], line]),
+    true,
+  );
+  assert(rli instanceof readline.Interface);
+  fi.emit('data', 'a\t');
+  rli.close();
+}
+
 [
   undefined,
   50,