[clang] [analyzer] Fix FP for cplusplus.placement new #149240 (PR #150161)

[Donát Nagy via cfe-commits]

NagyDonat wrote:

> I never understood the reasons of having metadata for placement-new.

I don't think that there is any real reason for it, but I guess that some compilers reused code from the code of non-placement new.

> Certainly on linux it was not the case, but I'm skeptical if it was on any other platforms such as Windows. (prove me wrong).

This (admittedly 16 years old) stackoverflow post claims that (at that time) Visual Studio added four bytes of overhead to an array allocated with placement new:
https://stackoverflow.com/questions/15254/can-placement-new-for-arrays-be-used-in-a-portable-way/75418614#75418614



https://github.com/llvm/llvm-project/pull/150161