[clang] [CIR] Upstream Re-Throw with no return (PR #154994)

[Amr Hesham via cfe-commits]

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@@ -405,17 +405,37 @@ void LoweringPreparePass::lowerArrayCtor(cir::ArrayCtor op) {
                              true);
 }
 
+void LoweringPreparePass::lowerThrowOp(ThrowOp op) {
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AmrDeveloper wrote:

I moved it, it was confusing that rethrow is in LP but throw in LowerToLLVM 🤔 

https://github.com/llvm/llvm-project/pull/154994