Revert FindGTK2 test debugging commits

Revert "FindGTK2: Avoid ctest truncation of output and make it verbose".
This reverts commit b7c15165a86a7a92150662b389bbcfb0ec165c6c.

Revert "FindGTK2: Print target info when building the tests".
This reverts commit ff69cecc2838127dc2c21e186abcae6bc1f56a15.
Merge topic 'FindGTK2-targets' into next

4782d12 Revert FindGTK2 test debugging commits