Merge: fix nitcc assert failure and nitcc continuous integration

Since #2573, some nitcc tests failed on a self-check (because the trim function did not correctly remove tags on trimmed nodes).

The bug was benign and easily fixable, but the subversion of the expectation was that the script kind of forgot about correctly reporting the error (an error message was printed but a success error code was returned). So the whole CI job was a success as failed tests where unreported.

Reported-by: Florian Deljarry <deljarry.florian@gmail.com>

Pull-Request: #2772