v8::Exception::CaptureStackTrace API addition

[James Snell]

Currently, for an embedder implementing a custom Web platform API like DOMException, it's a bit convoluted to capture the `stack` property. I'd like to contribute an implementation of a new C++ API `v8::Exception::CaptureStackTrace(...)` that would allow an embedder to attach the `stack` property to a given object.

I've drafted the proposed API change here: https://github.com/cloudflare/workerd/pull/1723/files#diff-625c48d5cbcb0c33165f4c43acdf961997f8cbd1bc5ba950b1c8ad979a3d0766

Not accounting for tests, the change itself is limited to v8-exception.h and api.cc