Remove old unused code from the core/sys/ directory

The `core/sys/` directory contains a two old, unused files that are removed with this patch: `profile.[ch]`, which was intended as a simple non-intrusive profiling mechanism but that never became a simple non-intrusive profiling mechanism, and `timetable.[ch]`, which was intended as a simple non-intrusive profiling mechanism but that never became a simple non-intrusive profiling mechanism.