[llvm] [X86] Place data in large sections for large code model (PR #70265)

[Fangrui Song via llvm-commits]

MaskRay wrote:

> I'm still of the opinion that large code model data should never contribute toward relocation pressure, but I'll follow gcc here.

The decision is deliberate. Some users may expect `.data.*` section name and build features on top of it. These users (say JIT programs) may not care about he small/large code model mixing story.
`-mlarge-data-threshold=` gives users choices.

https://github.com/llvm/llvm-project/pull/70265