[clang] [clang] Replace Sema::OffsetOfComponent with Designation (PR #199097)

[Yanzuo Liu via cfe-commits]

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

> Context: https://github.com/llvm/llvm-project/pull/195126, https://github.com/llvm/llvm-project/pull/194407, https://github.com/llvm/llvm-project/pull/195126

Two 195126?

https://github.com/llvm/llvm-project/pull/199097