[clang] [clang] Report erroneous floating point results in _Complex math (PR #90588)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

The changes seem reasonable to me, but I'd like to hear from @jcranmer-intel and/or @hubert-reinterpretcast in terms of whether they agree with this direction.

https://github.com/llvm/llvm-project/pull/90588