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

[Erich Keane via cfe-commits]

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

I think this is right.  I'm happy to let this go and see what happens.

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