org-element: Optimize affiliated keywords parsing

* lisp/org-element.el (org-element-center-block-parser,
  org-element-drawer-parser, org-element-dynamic-block-parser,
  org-element-footnote-definition-parser,
  org-element-plain-list-parser, org-element-quote-block-parser,
  org-element-special-block-parser, org-element-babel-call-parser,
  org-element-comment-parser, org-element-comment-block-parser,
  org-element-example-block-parser, org-element-export-block-parser,
  org-element-fixed-width-parser, org-element-horizontal-rule-parser,
  org-element-keyword-parser, org-element-latex-environment-parser,
  org-element-paragraph-parser, org-element-property-drawer-parser,
  org-element-src-block-parser, org-element-table-parser,
  org-element-verse-block-parser): Change signature. Now use an
  additional argument: affiliated.
(org-element--current-element): Skip affiliated keywords and pass them
  as an argument to parsers.  It prevents to walk through these
  keywords twice: the first time to get to the first line of the
  element, and a second time to collect the affiliated keywords.
* contrib/lisp/org-export.el (org-export-get-caption): Update function
  since multiple affiliated keywords are now reversed.
* testing/lisp/test-org-element.el: Update tests.

contrib/lisp/org-export.el

@@ -2912,7 +2912,7 @@ Caption lines are separated by a white space."
     (dolist (line full-caption (cdr caption))
       (let ((cap (funcall (if shortp 'cdr 'car) line)))
 	(when cap
-	  (setq caption (nconc caption (list " ") (copy-sequence cap))))))))
+	  (setq caption (nconc (list " ") (copy-sequence cap) caption)))))))
 
 
 ;;;; For Export Snippets

testing/lisp/test-org-element.el

@@ -168,7 +168,7 @@ Some other text
   ;; Parse multiple keywords.
   (should
    (equal
-    '("line1" "line2")
+    '("line2" "line1")
     (org-element-property
      :attr_ascii
      (org-test-with-temp-text
@@ -189,7 +189,7 @@ Some other text
   ;; Allow multiple caption keywords.
   (should
    (equal
-    '((("l1") "s1") (("l2") "s2"))
+    '((("l2") "s2") (("l1") "s1"))
     (org-test-with-temp-text "#+CAPTION[s1]: l1\n#+CAPTION[s2]: l2\nParagraph"
       (org-element-property :caption (org-element-at-point))))))
 
@@ -1692,7 +1692,7 @@ Outside list"
   (should
    (equal
     (org-element-interpret-data
-     '(org-data nil (paragraph (:attr_ascii ("line1" "line2")) "Paragraph")))
+     '(org-data nil (paragraph (:attr_ascii ("line2" "line1")) "Paragraph")))
     "#+ATTR_ASCII: line1\n#+ATTR_ASCII: line2\nParagraph\n"))
   ;; Interpret parsed keywords.
   (should
@@ -1711,7 +1711,7 @@ Outside list"
    (equal
     (org-element-interpret-data
      '(org-data nil (paragraph
-		     (:caption ((("l1") "s1") (("l2") "s2"))) "Paragraph")))
+		     (:caption ((("l2") "s2") (("l1") "s1"))) "Paragraph")))
     "#+CAPTION[s1]: l1\n#+CAPTION[s2]: l2\nParagraph\n")))
 
 (ert-deftest test-org-element/center-block-interpreter ()