With GCC/Clang, use O3 instead of O2.
With GCC/Clang, use O3 instead of O2.

The tests take the same time to run either way.

opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core