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

[via llvm-commits]

eleviant wrote:

> (invoked from LTO.cpp via readIRSymtab, and the flags are later checked when adding symbols in addModuleToGlobalRes)

Thanks a lot, I somehow missed that. Updated the patch

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