org-element: Do not parse timestamps within planning line

* lisp/org-element.el (org-element-context): Do not parse timestamps
  within planning line.
* testing/lisp/test-org-element.el (test-org-element/context): Remove test.

Strictly speaking, timestamps within planning lines are parameters
values that use timestamp syntax, not real timestamps belonging to the
document contents.

lisp/org-element.el

@@ -5867,17 +5867,6 @@ Providing it allows for quicker computation."
 		    (or (< pos cend) (and (= pos cend) (eobp))))
 	       (narrow-to-region cbeg cend)
 	     (throw 'objects-forbidden element))))
-	;; At a planning line, if point is at a timestamp, return it,
-	;; otherwise, return element.
-	((eq type 'planning)
-	 (dolist (p '(:closed :deadline :scheduled))
-	   (let ((timestamp (org-element-property p element)))
-	     (when (and timestamp
-			(<= (org-element-property :begin timestamp) pos)
-			(> (org-element-property :end timestamp) pos))
-	       (throw 'objects-forbidden timestamp))))
-	 ;; All other locations cannot contain objects: bail out.
-	 (throw 'objects-forbidden element))
 	(t (throw 'objects-forbidden element)))
        (goto-char (point-min))
        (let ((restriction (org-element-restriction type))

testing/lisp/test-org-element.el

@@ -3417,15 +3417,6 @@ Text
    (eq 'table-cell
        (org-test-with-temp-text "| a | b<point> {{{macro}}} |"
 	 (org-element-type (org-element-context)))))
-  ;; Find objects in planning lines.
-  (should
-   (eq 'timestamp
-       (org-test-with-temp-text "* H\n  SCHEDULED: <2012<point>-03-29 thu.>"
-	 (org-element-type (org-element-context)))))
-  (should-not
-   (eq 'timestamp
-       (org-test-with-temp-text "* H\n  SCHEDULED<point>: <2012-03-29 thu.>"
-	 (org-element-type (org-element-context)))))
   ;; Find objects in item tags.
   (should
    (eq 'bold