Implement DOMParentNode::replaceChildren()

[nielsdos]

ref: https://dom.spec.whatwg.org/#dom-parentnode-replacechildren

This is based on the fix in #11698, but I will rebase once that PR is merged.

[nielsdos]

Hmmm, crashes in CI but not locally, I'll investigate.

[nielsdos]

I think I fixed it... I initialized the argument count for the variadic arguments to zero. Apparently the "*" specifier doesn't fill in the zval* or uint32_t argument count when it is the only specifier?? That feels like a bug on its own to me, or at least a footgun.
Let's see what CI says first though

[Girgias]

I think I fixed it... I initialized the argument count for the variadic arguments to zero. Apparently the "*" specifier doesn't fill in the zval* or uint32_t argument count when it is the only specifier?? That feels like a bug on its own to me, or at least a footgun. Let's see what CI says first though

That does seem... odd

[Girgias]

LGTM