Otherwise, calling `Sem().Get()` on an empty loop continuing block
will return nullptr, which causes issues when inspecting the semantic
information of ast::BlockStatement nodes generically.
Change-Id: Ib3665b750c96eda02355fa879cf6300b8d69293a
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/89721
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
8e68f0aad7