Fix EchoTitleLocalCacheTest::testGet corner case
EchoTitleLocalCache title cache resolution ends up querying the database
to resolve title id to Title object.
In some corner case, we might only have one page in the database (UTPage
as provided by MediaWikiTestCase), thus the id 2 would not resolve to a
Title breaking the test.
Use insertPage() to ensure we have a second page.