ONSAM-1897 re-add enable_testing command to CMakeLists.txt (#2360)

Co-authored-by: Urszula Guminska <urszula.zofia.guminska@intel.com>

Author: krzeszew

Publications/GPU-Opt-Guide/CMakeLists.txt

@@ -9,6 +9,7 @@ if (BUILD_FORTRAN_EXAMPLES)
   set(CMAKE_Fortran_COMPILER ifx)
 endif()
 
+enable_testing()
 
 project(GPUOptGuide
   LANGUAGES ${_languages}