Git commits in Moodle 3.3.4 by Matt Clarkson

commit ec85b1eb566232d27ae5ef6acff75d7b1ad8bad7
Author: Matt Clarkson <mattc@catalyst.net.nz>
Date:   Wed, 06 Dec 2017 05:41:01 +0800
Tag:    v3.3.4

MDL-60976 dml: Optimise replace_all_text()