bug#33201: 26.1; Edebug doesn't work on closures with edebug-unwrap-results

[Allen Li]

Reproduce:

1. emacs -Q
2. Evaluate in *scratch*:

(setq edebug-unwrap-results t)

(defun foobar (x)
  (funcall x))

3. Evaluate to confirm it works:

(foobar '(closure ((x . 5) t) nil x))

4. Instrument foobar (C-u C-M-x with point on defun).
5. Evaluate:

(foobar '(closure ((x . 5) t) nil x))

5. Step through with SPC

Expected:

Evaluates to 5 with no error

Actual:

edebug-signal: Wrong type argument: listp, 5

In GNU Emacs 26.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.30)
 of 2018-07-05 built on juergen
Windowing system distributor 'The X.Org Foundation', version 11.0.12003000