[clang] [llvm] [WebAssembly] Implement an alternative translation for -wasm-enable-sjlj (PR #84137)

[Heejin Ahn via llvm-commits]

aheejin wrote:

I'm not sure about the common practice in this repo, but Github in general supports merge workflows much better. Especially in a long-running large PRs, if you force-push, it's hard for the reviewers to know what has changed since their last review, because all the history his lost and they have to look at the whole diff again. And many PRs in this repo tend to be bigger and long-running than other repos in my opinion.

Also Github supports a nice feature called "New changed since you last reviewed" 
![image](https://github.com/llvm/llvm-project/assets/8726997/72b62f34-86a3-4195-9a17-9a8276d2a886) and this feature is usable only with the merge workflow. (The screenshot is not mine; I got it from Google) I wonder why the merge workflow is harder to review.

https://github.com/llvm/llvm-project/pull/84137