After merging https://gerrit.wikimedia.org/r/#/c/400685/ (later re-submitted as https://gerrit.wikimedia.org/r/#/c/401699/) PHP 5.5 (wiki language set to Russian) job of Wikibase's Travis CI build started to fail with the segmentation fault, see e.g. https://travis-ci.org/wikimedia/mediawiki-extensions-Wikibase/builds/324099938 or https://travis-ci.org/wikimedia/mediawiki-extensions-Wikibase/builds/324502805.
The failure seems suspicious as there is little indication the segmentation fault would be related to the code change. PHP 5.5 build on Jenkins (though using slightly different setting with English wiki language and mysql instead of sqlite) does not cause any of such failure.