[clang] [Clang][Driver] Override complex number calculation method by -fno-fast-math (PR #132680)

[Shunsuke Watanabe via cfe-commits]

s-watanabe314 wrote:

Thank you for the review! I will also merge a minor change to initialize `ComplexRangeStr` and `GccRangeComplexOption` together.

https://github.com/llvm/llvm-project/pull/132680