Correct addition-precedence test so it would be a different output if it was wrong.

Author: Crell

Zend/tests/pipe_operator/precedence_addition.phpt

@@ -4,7 +4,7 @@ Pipe binds lower than addition
 <?php
 
 function _test1(int $a): int {
-    return $a + 1;
+    return $a * 2;
 }
 
 $bad_func = null;
@@ -14,4 +14,4 @@ $res1 = 5 + 2 |>  '_test1';
 var_dump($res1);
 ?>
 --EXPECT--
-int(8)
+int(14)