[llvm] [Bolt] fix a wrong relocation update issue with weak references (PR #69136)

[Vladislav Khmelevsky via llvm-commits]

yota9 wrote:

Hi @linsinan1995 . May I ask in what what it might impact it? Does some linkers removes the symbol name?
We're trying to avoid yaml tests. If it completely necessary we need to minimise yaml file (e.g. removing the symbols and sections that are not related to the test). 

> I still use IsWeakReference, since weak reference is a term for such a case. Is it ok?

Corrent me if I'm wrong but the weak reference doesn't always mean that the symbol is NULL. You're looking to the 2 parameters: weak and undefined, that is why I was asking to add both weak and und to the lambda name.

https://github.com/llvm/llvm-project/pull/69136