Falco unit tests

Intro

Under unit_tests/engine and unit_tests/falco directories, we have different test suites that could be a single file or an entire directory according to the number and the complexity of tests.

Build and Run

cmake -DMINIMAL_BUILD=On -DBUILD_DRIVER=Off -DBUILD_FALCO_UNIT_TESTS=On ..
make falco_unit_tests
sudo ./unit_tests/falco_unit_tests