[clang] [Clang][OpenMP] Fix crash on a `braced-init-list` in the `init` or increment of a transformed loop (PR #233248)

[Akash Manna via cfe-commits]

akash-manna-sky wrote:

> Why do we want to reject this, why not fix handling of this kind of initializers?

I considered `{}` as outside the canonical form, since the spec wants an expression there and GCC rejects every braced spelling. It is now handled as the value-initialized zero of the counter type, so `int i = {}` and `i += {}` are analysed like `0`.


https://github.com/llvm/llvm-project/pull/233248