Make qmediaplayerbackend::processEOS test less flaky.

Change-Id: Ib961f3d4e238a156dc2e1ade1828ae8f1bf5b755
Reviewed-by: Christian Stromme <christian.stromme@theqtcompany.com>

tests/auto/integration/qmediaplayerbackend/tst_qmediaplayerbackend.cpp

@@ -478,7 +478,7 @@ void tst_QMediaPlayerBackend::processEOS()
 
     //position is reset to start
     QTRY_VERIFY(player.position() < 100);
-    QVERIFY(positionSpy.count() > 0);
+    QTRY_VERIFY(positionSpy.count() > 0);
     QCOMPARE(positionSpy.first()[0].value<qint64>(), 0);
 
     QCOMPARE(player.state(), QMediaPlayer::PlayingState);