Because Debian 7 and 8 run different versions of PHP, so unless you did something specific in the upgrade to avoid it, your PHP was almost certainly upgraded too, to 5.6. And it may be in a different place running with a different executable so your cron path is incorrect.
You'll need to locate that on your system. Here's some info: https://packages.debian.org/jessie/php5 to help out.
As Ken mentioned, you really only need to run one cron, the cli cron, from the command line. There's no reason to run both crons or to use wget. Just use the one calling php.
/usr/bin/php /path/to/moodle/admin/cli/cron.php
is the right format, you just need to replace the first part with where your php is actually located.