[clang] [Clang] Add float type support to __builtin_reduce_add and __builtin_reduce_multipy (PR #120367)

[Farzon Lotfi via cfe-commits]

farzonl wrote:

@RKSimon It looks like you started this work with: 

1. a23291b7db48670f7c57adcfb45877c826a97f22
2. 8a92c45e07dc81c83ca3afda3971d98c512429d4

If you have time could you take a look and let me know what you think?

https://github.com/llvm/llvm-project/pull/120367