[clang] [llvm] [clang] Implement pragma clang section on COFF targets (PR #112714)

[Vinicius Tadeu Zein via llvm-commits]

vtz wrote:

> This is an LLVM code change, not a clang code change. It's an important principle that we test LLVM at the smallest reasonable granularity. Can you replace the clang test with an IR test? I'm sure we already have existing IR carrying existing sections, we just need to test it with a new target.

@rnk this is also addressed with our new commit.

Please refer to my comment above and quoted below:
> I tried making a new test based on llvm/test/CodeGen/ARM/clang-section.ll, but it ended up equal so I added an extra RUN command to this test as well

https://github.com/llvm/llvm-project/pull/112714