MDL-40425 libraries: Deprecate context_instance_preload()
MDL-40425 libraries: Remove context_instance_preload() from core
MDL-40429 - Libraries: Deprecate get_contextlevel_name().
MDL-40430 - Libraries: Deprecate print_context_name().
MDL-40426 - Libraries: Deprecate mark_context_dirty().
MDL-40428 Libraries: Deprecated delete_context