[llvm] [IR][TBAA] Allow multiple fileds with same offset in TBAA struct-path (PR #76356)

[Bushev Dmitry via llvm-commits]

dybv-sc wrote:

> Though as a preliminary note from my side: This need a LangRef update to specify what exactly you're allowing here and what semantics it has.

@nikic, I've updated the LangRef

https://github.com/llvm/llvm-project/pull/76356