Description:
------------
When an array has been passed to array_walk, with a callback that accepts the first value by reference, and the array is then passed as an argument to array_replace_recursive, an apparent reference is created for each element of the array, which then triggers bug #71241.

The test script attached gives the correct output under php 5.6 and 5.5, but gives the wrong result under 7.0.8

Test script:
---------------
<?php

function walk (array $arr) {
	array_walk($arr, function (&$val, $name) {

	});

	return $arr;
}

$arr3 = ['foo' => 'foo'];
$arr4 = walk(['foo' => 'bar']);
$arr5 = array_replace_recursive($arr3, $arr4);
$arr5['foo'] = 'baz';

var_dump($arr3, $arr4, $arr5);


Expected result:
----------------
array(1) {
  'foo' =>
  string(3) "foo"
}
array(1) {
  'foo' =>
  string(3) "bar"
}
array(1) {
  'foo' =>
  string(3) "baz"
}


Actual result:
--------------
array(1) {
  ["foo"]=>
  string(3) "foo"
}
array(1) {
  ["foo"]=>
  &string(3) "baz"
}
array(1) {
  ["foo"]=>
  &string(3) "baz"
}