Description:
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When I create an object (DateTime), the second parameter (timezone) is ignored and uses UTC. The test script has a comparison with PHP 5.6.

Test script:
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<?php
date_default_timezone_set('UTC');

$dt = new DateTime('2016-04-22 17:00:00', new DateTimeZone('America/Sao_Paulo'));
echo $dt->getTimestamp();

// Result:
// 1461355200 (PHP 5.6.19) -> 04/22/2016 20:00 (UTC)
// 1461344400 (PHP 7.0.5)  -> 04/22/2016 17:00 (UTC)

echo '<br />';

$dt = new DateTime('2016-04-22 20:00:00', new DateTimeZone('UTC'));
$dt->setTimezone(new DateTimeZone('America/Sao_Paulo'));
echo $dt->getTimestamp();

// Result:
// 1461355200 (PHP 5.6.19) -> 04/22/2016 20:00 (UTC)
// 1461355200 (PHP 7.0.5)  -> 04/22/2016 20:00 (UTC)

Expected result:
----------------
1461355200
1461355200

Actual result:
--------------
1461344400
1461355200