[llvm] [WebAssembly] Diagnose llvm.clear_cache instead of aborting (PR #224579)

[Heejin Ahn via llvm-commits]

aheejin wrote:

> @aheejin the other option here would be to just implement this as a noop like on platforms like x86. Maybe that makes more sense?

I'm not sure. Apparently we had a discussion in https://reviews.llvm.org/D64322. Maybe in some cases no-ops are fine and more convenient, but given that the main purpose of using this function is to write instructions to the memory to run it, which is not supported in Wasm, it may be safe to error out and let users know what they are trying to do is not going to work?

https://github.com/llvm/llvm-project/pull/224579