[llvm] [Attributor] Teach HeapToStack about conservative GC allocators (PR #113299)

[Shilei Tian via llvm-commits]

shiltian wrote:

This PR needs to be separated into two: 1) add the support of `nofree` in `allockind` as well as the corresponding IR tests 2) use it in attributor as well as tests

https://github.com/llvm/llvm-project/pull/113299