Fix failing tests for readline() without input

If PHP readline extension is using libedit or readline the output is
different with the readline library also the prompt is output.

Author: petk

ext/readline/tests/readline_without_input.phpt

@@ -10,6 +10,6 @@ User Group: PHP-WVL & PHPGent #PHPTestFest
 var_dump(readline());
 var_dump(readline('Prompt:'));
 ?>
---EXPECT--
-bool(false)
+--EXPECTF--
 bool(false)
+%Abool(false)