I’ve run into the same problem. It worked on Saturday. This Monday it auto-upgraded to 7.0.10, now it breaks. I don’t have a fix, so here’s more information that MAY help debugging?
I’m on CentOS7 with cPanel’s EA brand of PHP.
PHP 7.0.10 (cgi-fcgi) (built: Aug 22 2016 20:34:53)
Copyright (c) 1997-2016 The PHP Group
Zend Engine v3.0.0, Copyright (c) 1998-2016 Zend Technologies
with Zend OPcache v7.0.10, Copyright (c) 1999-2016, by Zend Technologies
I’ve tried reinstalling PHP and wp-cli to no avail.