When importing test execution results, the first unmatched path should be logged with INFO

When importing a test execution report, the paths which are contained in the report and which cannot be mapped against a project test file are logged in DEBUG.
The problem is that nothing appears in default INFO mode.
That makes it harder for users to understand why they don't see the expected results in the SonarQube UI.
We can keep the DEBUG logs, but we should add one INFO log line giving the first unmatched path. This is already what we do when importing coverage reports.