[llvm] [coverage] Add option for keeping mappings order (PR #91600)

[via llvm-commits]

Lambdaris wrote:

Add two unit tests to check if the mappings are sorted.

> You might also create LIT cases in `llvm/test/tools/llvm-cov` for llvm-cov that rely on text-formatted profdata files for a mock example. But it'd be better to avoid relying on prebuilt binaries, if possible. I'd like to see what others suggest.

I'm not very clear. If we add the mock example, what llvm-cov does is expected? If the mappings are not sorted, llvm-cov would panic. Is it the expected behavior?


https://github.com/llvm/llvm-project/pull/91600