Remove 'concrete_bytes' fielddata impl from tests

We don't have this implementation anymore tests will just fallback
to default and issue a warning.
Add test method information to log output

Often it's hard to tell which testmethods were already executed
when a particualr test fails. This commit adds a log output when a
new test is started to better differentiate which log output belongs
to which test.

This commit also moves the reproduce line to logging output to gain
timestamps for the failure.