[clang] [clang][Sema] Handle target_clones redeclarations that omit the attribute (PR #169259)

[Yanzuo Liu via cfe-commits]

zwuis wrote:

Thank you for your patch! Please add a release note entry to "clang/docs/ReleaseNotes.rst" so that users can know the improvement.

https://github.com/llvm/llvm-project/pull/169259