[llvm] [AbstractCallSite] Handle Indirect Calls Properly (PR #163003)

[Nikita Popov via llvm-commits]

https://github.com/nikic approved this pull request.

LGTM, though I'm still unhappy with the commit message. Please optimize for maximum information density, not for maximum PR description length.

A sufficient description for this change would be something like:

> AbstractCallSite handles three types of call (direct, indirect and callback). Fix the handling of indirect calls in some methods, which incorrectly assumed that non-direct calls are always callback calls.

https://github.com/llvm/llvm-project/pull/163003