For Gitlab to detect and report the failing tests directly on the MR front page. This has the disadvantage of making the test job output more silent, but the results are still available as artifacts (in JUnit XML format), which hopefully should be enough if we need to have a better look at it. The tests standard output is included in the reports too.
I believe it would also show some failure statistics that could help deciding on whether a test is regularly failing or not, but I wasn't able to really test that it does. In order to help it doing it, it also implements hashing of test sources to generate test IDs that are more stable than `source:line`, although it could be done later.
All the succeeding (and todo) tests are grouped together and reported as once, as they would otherwise be split into individual success lines in the Gitlab UI, which would make it unnecessary large. Only failures and skipped tests are reported as individual entries.
-- v2: gitlab: Use winetest JUnit output mode. winetest: Implement JUnit report output mode. winetest: Introduce some test report helpers. winetest: Pass output file handle to xprintf. winetest: Always use a temporary file for test output. winetest: Add printf attributes to xprintf. winetest: Add printf attributes to strmake.