projects/library_files/c++: add missing files

The previous commit added this new testcase, but due to .gitignore
rules, missed the "*.gli" files (usually ignored as compilation
artifacts). Without these files, the testcase fails every time. "git add
-f" did the trick to add them.

TN: V816-018
Change-Id: I5e39ae565366958a8f588e959c4a3a67ffbbdd4a

Author: pmderodat