[!113] Fix parallel UG test

Merge branch 'feature/fix-parallel-construction-test' into 'master'

In time of dune-uggrid, mismatches of sequential UGGrid and parallel other code cannot happen, unless you screw up big time anyway.

This fixes #131

See merge request quality/dune-testtools!113

Closes #131 (closed)

(cherry picked from commit 3aeb4948)

96f7cc7b Fix parallel UG test