[clang] Revert "[Clang] disallow selectany on non-global-variable declarations" (PR #196511)

[Aaron Ballman via cfe-commits]

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

LGTM but I agree with @mstorsjo about updating the patch summary to have more details. Thanks for the quick revert!

https://github.com/llvm/llvm-project/pull/196511