Add support for WebAssembly exceptions in Wasmer

[syrusakbary]

We'll need to add support for exception handling in Wasmer (runtime/VM level):

https://github.com/WebAssembly/exception-handling

Basically, Wasmer needs add the exception-handling WAST tests to our repo, and also pass them.
https://github.com/WebAssembly/exception-handling/tree/main/test/core

Note: we can start with singlepass, then LLVM and Cranelift last (it might be a bit harder in cranelift or require a fork, so we'll leave it to be the last one)

[syrusakbary]

This is priority low because we need to work in threads first. Once threading is done, we can work on this

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[aykevl]

Bumping this because the stale bot can't determine priorities.