[llvm] [X86][GlobalISel] Support G_FADD, G_FSUB, G_FMUL, G_FDIV (PR #87339)

[Thorsten Schütt via llvm-commits]

tschuett wrote:

If you look at the AArch64 [legalizer](https://github.com/llvm/llvm-project/blob/4cd7bb07c7540bf83a7a60a67aa282e99461ca2f/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp#L243), you will see that it use `clampNumElements`. The number of max elements differs between float and double.

https://github.com/llvm/llvm-project/pull/87339