[selenium] Merge some editmerge tests
Setting up the conflict is very expensive. Testing some of these
things independent form each other does not gain much or does not
even make sense.
This is a first step moving a lot of things together also inspired
by the structure used in the tourdialog spec. The test should
still be quite independent of each other.
Further cleanup will follow including some refactoring for the
assertions. Just want to keep the commits not too crazy.