[!397] Bugfix in assertion if blocking is possible
Merge branch 'fix/assert-if-blocking-is-possible' into 'master'
See merge request pdelab/dune-pdelab!397
(cherry picked from commit 2dd3829a)
e7c73d33 Bugfix in assertion if blocking is possible 471e1ca2 Don't catch exceptions in testordering 81e74c3b Fix a number of problems in testordering