[clang] Reapply "[Clang][Sema] placement new initializes typedef array with correct size (#83124)" (PR #89036)

[via cfe-commits]

awson wrote:

It looks like the author of the patch have either diverted to other activities or is unable to fix it.

Could we, perhaps, **just diagnose** the situation and gracefully fail with something like "typedefed array blah-blah is not supported in blah-blah" instead of generating segfaulting code?

https://github.com/llvm/llvm-project/pull/89036