[clang] [clang][Sema] Fix the continue and break scope for while loops (PR #152606)

[Oliver Hunt via cfe-commits]

ojhunt wrote:

Actually pushing the codegen changes, but I found test failures when I ran the full test suite which means I'm concerned about the exact semantics. Given those failures I'm going to make this a draft again until I can spend enough time to be more sure about the full semantic and codegen correctness.

https://github.com/llvm/llvm-project/pull/152606