main/php: security upgrade to 5.6.27. Fixes #6193

CVE-2016-7411: A memory corruption error may occur during deserialized object destruction
CVE-2016-7412: A heap overflow may occur in the processing of BIT fields in mysqlnd
CVE-2016-7413: A use-after-free memory error may occur in wddx_deserialize()
CVE-2016-7414: An out-of-bounds memory error may occur in phar_parse_zipfile()
CVE-2016-7416: A memory corruption error may occur in processing locale data
CVE-2016-7417: A memory corruption error may occur when unserializing SplArray
CVE-2016-7418: An out-of-bounds memory read error may occur in php_wddx_push_element()
(cherry picked from commit c498273a)