Whenever we run tests *with* the tileManager, we cannot inspect any grid/tiles related things, because all these get asynchronous, so don't use tileManager in all the tests
there were 2 more failing tests, do not include tileManager there as well
make iframe visible in TileManager tests so that they pass in FF as well
Merge pull request #1003 from openlayers/notilemgrtest

Whenever we run tests *with* the tileManager, we cannot inspect any grid...(r=@ahocevar)