Fix risky tests

PHPUnit 4.0.14

There were 6 risky tests:

1) Wikibase\Test\SerializationOptionsTest::testSetOptions with data set #0 (array(), array())
This test did not perform any assertions

/var/www/phase3/tests/phpunit/MediaWikiTestCase.php:133
/usr/bin/phpunit.phar:583
/usr/share/pear/PHPUnit/Runner/Version.php:3

2) Wikibase\Test\SerializationOptionsTest::testMerge with data set #0 (array(), array())
This test did not perform any assertions

/var/www/phase3/tests/phpunit/MediaWikiTestCase.php:133
/usr/bin/phpunit.phar:583
/usr/share/pear/PHPUnit/Runner/Version.php:3

Change-Id: I71faf8cf235cc5cc2fd2097c288ba78a47bdfe67
Merge "Fix risky tests"