[clang] [clang] Disable type-aware allocator lookup for older C++ versions (PR #213430)

[via cfe-commits]

nots1dd wrote:

@Sirraide apologies for pinging for a review, I cant seem to be able to request it (and your name was in the Maintainers.md file for clang/Sema) if you could take a look thatd be great

https://github.com/llvm/llvm-project/pull/213430