[Patch] Extension tests fail on dynamic ext dependency

Hi, could someone validate and, if considered OK, merge the following PR: https://github.com/php/php-src/pull/1602 This is a follow-up to a previous patch by Derick to enable testing extensions with a dependency to another (dynamic) extension. More details in the corresponding bug report : https://bugs.php.net/bug.php?id=70781 Considering it affects very few people, there's no need to merge it in 7.0, but it would be nice to have it fixed in the next 5.6.x and 7.x releases. Thanks François