[php-src] Issue #10005: Wrong with prev February

Issue: https://github.com/php/php-src/issues/10005 Author: hormus ### Description The following code (from php >= 5.3: ```php <?php $utc = new \DateTimeZone('UTC'); $london = new \DateTimeZone('Europe/London'); $test1 = new \DateTime('2018-01-31 00:00:00', $utc); $test2 = new \DateTime('2018-03-30 23:00:00', $utc); //$dateDiff = $test2->diff($test1); // true absolute Should the interval be forced to be positive $dateDiff = $test1->diff($test2); $bugs = array('y' => &$dateDiff->y, 'm' => &$dateDiff->m, 'd' => &$dateDiff->d, 'h' => &$dateDiff->h, 'invert' => &$dateDiff->invert, 'days' => &$dateDiff->days); $test3 = new \DateTime('+2 month ' . $test1->format('Y-m-d\\TH:i:s\\Z')); $test4 = $test2->sub($dateDiff); var_dump($test4->format('Y-m-d H:i:s +00:00'), $bugs); ?> ``` Resulted in this output: ```code string(26) "2018-02-03 00:00:00 +00:00" array(6) { ["y"]=> int(0) ["m"]=> int(1) ["d"]=> int(27) ["h"]=> int(23) ["invert"]=> int(0) ["days"]=> int(58) } ``` But I expected this output instead: ```code string(26) "2018-01-31 00:00:00 +00:00" array(6) { ["y"]=> int(0) ["m"]=> int(1) ["d"]=> int(27) ["h"]=> int(23) ["invert"]=> int(0) ["days"]=> int(58) } ``` ### PHP Version Any ### Operating System _No response_