When running `codegen/box` tests, Kotlin/Native test infrastructure
divides test data files into groups and compiles each group in a single
compilation.
As a result, compilation problem with one test can cause an unrelated
nearby test to fail.
To make this less frustrating, this commit adjusts test failure reports:
it moves the test grouping mention from the bottom of a report to the
top and makes the wording more clear and actionable.
Svyatoslav Scherbina
8a8eb18efd