[clang] [llvm] [X86] Set .llvmbc and .llvmcmd to exclude sections (PR #151910)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> > I think `-ffat-lto-objects` uses exclude metadata, but I'm not overly familiar with what that's intended to do.
> 
> Effect of exclude kind: https://discourse.llvm.org/t/end-to-end-fembed-bitcode-llvmbc-and-llvmcmd/56265/14?u=haohaiwen

I know what the exclude option there does, I'm the one who added that feature for the offloading toolchains. I was referring to `-ffat-lto-objects` versus the other LTO embedding.

https://github.com/llvm/llvm-project/pull/151910