[Bug middle-end/69919] pool allocator and mem-stat race at program exit

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69919

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Or maybe simply making mem_alloc_description::~mem_alloc_description () empty.