Preserve file local variables during some operations
* lisp/org-macs.el (org-preserve-local-variables): New macro.
* lisp/org-footnote.el (org-footnote--clear-footnote-section):
(org-footnote--goto-local-insertion-point):
(org-footnote-create-definition):
(org-footnote-delete):
(org-footnote-renumber-fn:N):
(org-footnote-sort):
(org-footnote-normalize):
* lisp/org.el (org-move-subtree-down):
(org-copy-subtree):
(org-sort-entries):
(org-refile): Use new macro.
* testing/lisp/test-org-footnote.el (test-org-footnote/normalize):
(test-org-footnote/delete):
(test-org-footnote/sort):
(test-org-footnote/normalize):
* testing/lisp/test-org.el (test-org/sort-entries): Add tests.
Operations affected include copying, killing, refiling, archiving and
moving subtrees. It also affects sorting, creating and deleting
footnotes.