Move responsibility for creating result to emitter

[thekid]

This way, emitters can control the implementation they want to work with.

[thekid]

...and Result should be an abstract base class with a slim interface

[thekid]

...and Result should be an abstract base class with a slim interface

@FileSystemCL<./src/main/php>
public class lang.ast.emit.Result implements lang.Closeable {
  public var $out
  public var $codegen
  public var $meta
  public var $locals
  public var $stack

  public function __construct(io.streams.OutputStream $out)

  protected function initialize(): void
  protected function finalize(): void
  public function close(): void
}