MDL-40405 libraries: Fix PHPDoc and debugging assertion
MDL-40406 libraries: Deprecate create_contexts()
MDL-40406 libraries: Deprecate cleanup_contexts()
MDL-40406 libraries: Deprecate build_context_path()
MDL-40406 libraries: Deprecate rebuild_contexts()
MDL-40407 Libraries: deprecated preload_course_contexts
MDL-40425 libraries: Deprecate context_instance_preload()
MDL-40425 libraries: Remove context_instance_preload() from core