fix test output

Now that the ASPECT tester is running again, it is time to fix a couple of test outputs.

Sadly, we now have a problem:
I am running the tests with gcc and with clang with the static analyzer. For far this worked well, but now gcc and clang produce different output for 3 tests. See http://cdash.kyomu.43-1.org/viewTest.php?onlyfailed&buildid=11454
For two of them it is tracer data. The numbers are quite different though, so I wonder if there this is a bug in the tracer code. We could remove the .vtu files from the comparison. Thoughts?

The last test (burstedde) takes 57 Stokes iterations with clang, while gcc takes 54. It is strange that the number of iterations is different, because I am using the same Trilinos installation. Thoughts?