[llvm] Revert "ValueTracking: Improve handling of fadd in computeKnownFPClass." (PR #174290)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

Yeah, wondering if I copied and pasted that wrong. `libc.test.src.math.smoke.log1p_test.__unit__ ` was failing too though.

https://github.com/llvm/llvm-project/pull/174290