[CIR] Fix ordering of lifetime-extended cleanups (#200874) We had a bug that was causing any lifetime-extended cleanups that occurred within a full-expression cleanup scope to be emitted prematurely when the expression also required deferred conditional cleanups. This was, in some cases, causing a dangling reference to temporaries that had already been destructed. Luckily, it was also causing us to not emit a return at the end of the function in one case, leading the verifier to draw attention to this problem. This change introduces new functions in RunCleanupsScope to allow "ordinary" EH stack cleanups to be force-emitted separately from lifetime-extended cleanups. Classic codegen doesn't need this capability because it handles deferred conditional cleanups very differently than CIR due to its flat/branching approach. The testing for this fix did uncover a significant issue wherein CIR is calling destructors in the wrong order even after the fix in this PR. However, that's a pre-existing issue that will require changes beyond the scope of this fix, so I'll handle it in a follow-up. Assisted-by: Cursor / claude-opus-4.7
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