Resolves to the absolute normalized path, with symbolic links resolved.

// e.g. given /home/alice/file.txt and current directory /home/alice
await Deno.symlink("file.txt", "symlink_file.txt");
const realPath = await Deno.realPath("./file.txt");
const realSymLinkPath = await Deno.realPath("./symlink_file.txt");
console.log(realPath);  // outputs "/home/alice/file.txt"
console.log(realSymLinkPath);  // outputs "/home/alice/file.txt"

Requires allow-read permission for the target path. Also requires allow-read permission for the CWD if the target path is relative.