[Bug c++/90243] diagnostic notes that belong to a suppressed error about an uninitialized variable in a constexpr function are still shown

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90243

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Patch posted to https://gcc.gnu.org/ml/gcc-patches/2019-04/msg01009.html