As a Wikibase developer, I want the Travis CI tests to succeed in order to avoid being spammed by emails.

Problem:
Travis CI for Wikibase has been failing since build #11838, 2019-08-27. It only fails on builds where the language is not English, with the following error:

1) Wikibase\DataAccess\Tests\MediaWiki\EntitySourceDocumentUrlProviderTest::testGivenLocalWikiSource_urlOfLocalWikiIsUsed
Failed asserting that two arrays are equal.
--- Expected
+++ Actual
@@ @@
 Array (
-    'local' => 'http://foo.test/wiki/Special:EntityData/'
+    'local' => 'http://foo.test/wiki/%D0%A1%D0%BB%D1%83%D0%B6%D0%B5%D0%B1%D0%BD%D0%B0%D1%8F:EntityData/'
/home/travis/build/wikimedia/phase3/extensions/Wikibase/data-access/tests/phpunit/MediaWiki/EntitySourceDocumentUrlProviderTest.php:39
/home/travis/build/wikimedia/phase3/tests/phpunit/MediaWikiIntegrationTestCase.php:451
/home/travis/build/wikimedia/phase3/maintenance/doMaintenance.php:99

The last successful build is #11837; the git diff between the two builds is only a single commit (plus its merge) adding the test that fails here: I9fe06458cf, linked to T214557 and T211799.

I suspect that this test simply doesn’t work on non-English wikis, and neither its developers nor our Wikimedia CI tested for that – only Travis CI does: we have jobs in Arabic and Russian. (As it happens, those are also the PHP7 jobs whereas the PHP7.1 and PHP7.2 jobs are in English, but I think this is more likely to be due to the language, not the PHP version.)

Example:
https://travis-ci.org/wikimedia/mediawiki-extensions-Wikibase/builds/577484886

Acceptance criteria:

• Travis CI for Wikibase is green again.