Wikibase\Lib\Tests\SimpleCacheWithBagOStuffTest::testSetMultipleTtl Failed asserting that null matches expected 'value2'.
Caused tests to intermittently fail for https://gerrit.wikimedia.org/r/#/c/mediawiki/core/+/450936/.
Follows-up rEWBAcf03dc4cc8ae: Implementation of `Psr\SimpleCache\CacheInterface` using `BagOStuff`.