Support URL overload for `Deno.chdir`

Editor assessment

The subject states the new capability exactly: Deno.chdir accepts a URL overload. Type feat and scope cli are accurate, the API and the accepted type are named, and no body is needed because the interface change is fully described. No footers beyond the PR number. Hygiene is clean: imperative, short, no junk. A tight, complete message for a small, well-bounded input-flexibility addition to a familiar API.