[llvm] [clang] [Instrumentation][X86] Limit setting large section flag to medium/large code models (PR #75542)

[Arthur Eubanks via cfe-commits]

aeubanks wrote:

Actually I'm going to go down the `Module::getCodeModel()` route. Right now I think frontends adding module metadata for the code model is probably not common, but we should aim for that. And this will in the short term still work for Fuchsia without breaking API for other frontends. It just makes updating tests more annoying since now they have to ingest IR with the proper code model metadata.

https://github.com/llvm/llvm-project/pull/75542