[Bug c++/100111] [10/11 Regression] `-fno-elide-constructors` with `constexpr` ctors causes ICE in GCC 10.3

[lh_mouse at 126 dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100111

--- Comment #6 from Liu Hao <lh_mouse at 126 dot com> ---
I have bootstrapped GCC 10.3.1 on `i686,x86_64}-w64-mingw32` successfully and
verified that this patch fixed the error.