Description:
------------
All the same, the value of element
Non-compatible features have been found in the function.

arsort()


PHP 5.2 ~ 5.6 result
----
array(4) {
  ["d"]=>
  int(1)
  ["c"]=>
  int(1)
  ["z"]=>
  int(1)
  ["a"]=>
  int(1)
}


PHP 7.0 result
----
array(4) {
  ["a"]=>
  int(1)
  ["z"]=>
  int(1)
  ["c"]=>
  int(1)
  ["d"]=>
  int(1)
}

Test script:
---------------
<?php
$arr = array(
    'a' => 1,
    'z' => 1,
    'c' => 1,
    'd' => 1
);

arsort($arr);
var_dump($arr);


Expected result:
----------------
array(4) {
  ["d"]=>
  int(1)
  ["c"]=>
  int(1)
  ["z"]=>
  int(1)
  ["a"]=>
  int(1)
}

Actual result:
--------------
array(4) {
  ["a"]=>
  int(1)
  ["z"]=>
  int(1)
  ["c"]=>
  int(1)
  ["d"]=>
  int(1)
}