[llvm] [WebAssembly] Add unreachable before catch destinations (PR #123915)

[Derek Schuff via llvm-commits]

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@@ -1358,6 +1359,13 @@ WebAssemblyCFGStackify::getTrampolineBlock(MachineBasicBlock *UnwindDest) {
   BuildMI(TrampolineBB, EndDebugLoc, TII.get(WebAssembly::THROW_REF))
       .addReg(ExnReg);
 
+  // The trampoline BB's return type is exnref because it is a target of
+  // catch_all_ref. But the body type of the blodk we just created is not. We
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dschuff wrote:

```suggestion
  // catch_all_ref. But the body type of the block we just created is not. We
```

https://github.com/llvm/llvm-project/pull/123915