[llvm] [ThinLTO] Don't mark calloc function dead (PR #72673)

[Steven Wu via llvm-commits]

cachemeifyoucan wrote:

Right, I don't think it is correct to special case `calloc` or any function. In general, this kind of functions are handled by preserving all `RuntimeLibcalls`. I wonder if we should consider just adding all the allocation functions that backend understand into that list, then it can be handled automatically.

And yes, test needs to be simplified to drop all redundant IR that is not related to tests.

https://github.com/llvm/llvm-project/pull/72673