Cleanup: move CMake test utility functions into testing.cmake

Combining functions from macros.cmake and Modules/GTestTesting.cmake.
It was unusual to have Blender specific code in the Modules folder.

intern/libmv/CMakeLists.txt

@@ -198,8 +198,6 @@ if(WITH_LIBMV)
 
 
   if(WITH_GTESTS)
-    include(GTestTesting)
-
     blender_add_lib(libmv_test_dataset "./libmv/multiview/test_data_sets.cc" "${INC}" "${INC_SYS}" "")
 
     blender_add_test_executable("libmv_predict_tracks" "./libmv/autotrack/predict_tracks_test.cc" "${INC}" "${INC_SYS}" "libmv_test_dataset;bf_intern_libmv;extern_ceres")

intern/libmv/bundle.sh

@@ -190,8 +190,6 @@ ${third_headers}
 
 
   if(WITH_GTESTS)
-    include(GTestTesting)
-
     blender_add_lib(libmv_test_dataset "./libmv/multiview/test_data_sets.cc" "\${INC}" "\${INC_SYS}" "")
 
 ${tests}