[clang] Add flag to suppress overflow errors in C++ constant expressions. (PR #102390)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

Thank you for putting together the experiment @efriedma-quic, it's greatly appreciated! I agree with closing it for now; we can resurrect it later if necessary.

https://github.com/llvm/llvm-project/pull/102390