Remove useless unwind-protect forms, or make them useful as intended

* lisp/imenu.el (imenu--generic-function):
* lisp/mail/yenc.el (yenc-decode-region):
* lisp/textmodes/table.el (table-recognize-region):
* test/lisp/dired-tests.el (dired-test-directory-files):
* test/lisp/hl-line-tests.el (hl-line-tests-sticky):
Fix unwind-protect bracketing mistakes that caused the unwind code to
be misplaced.
* lisp/strokes.el (strokes-read-stroke): Fix a bracketing mistake that
misplaced the unwind code, and another one that misplaced the
else-clause of an `if` form.
* test/lisp/gnus/mml-sec-tests.el (mml-secure-test-fixture): Fix a
bracketing mistake that misplaced the unwind code, and remove
superfluous condition-case.

* lisp/mwheel.el (mouse-wheel-global-text-scale):
* lisp/speedbar.el (speedbar-stealthy-updates)
(speedbar-fetch-dynamic-etags):
* lisp/emacs-lisp/edebug.el (edebug--recursive-edit):
* lisp/emacs-lisp/package.el (package--read-pkg-desc):
* lisp/cedet/semantic.el (semantic-refresh-tags-safe):
* lisp/emulation/viper-cmd.el (viper-escape-to-state):
* lisp/emulation/viper-cmd.el (viper-file-add-suffix):
* lisp/gnus/mail-source.el (mail-source-movemail):
* lisp/mail/feedmail.el (feedmail-send-it-immediately)
(feedmail-deduce-address-list):
* lisp/mail/mailclient.el (mailclient-send-it):
* lisp/mail/smtpmail.el (smtpmail-deduce-address-list):
* lisp/mh-e/mh-print.el (mh-ps-print-range):
* lisp/textmodes/reftex-index.el (reftex-index-this-phrase):
* test/lisp/emacs-lisp/ert-tests.el (ert-test-run-tests-batch):
(ert-test-run-tests-batch-expensive):
Remove unwind-protect forms that are apparently useless, some since a
prior edit that removed their purpose, some since their first
appearance.

* test/lisp/subr-tests.el (subr-test--frames-2):
Insert dummy unwind form in backtrace test code.

lisp/gnus/mail-source.el

@@ -658,50 +658,49 @@ Deleting old (> %s day(s)) incoming mail file `%s'." diff bfile)
 	;; If getting from mail spool directory, use movemail to move
 	;; rather than just renaming, so as to interlock with the
 	;; mailer.
-	(unwind-protect
-	    (save-excursion
-	      (setq errors (generate-new-buffer " *mail source loss*"))
-	      (let ((default-directory "/"))
-		(setq result
-		      ;; call-process looks in exec-path, which
-		      ;; contains exec-directory, so will find
-		      ;; Mailutils movemail if it exists, else it will
-		      ;; find "our" movemail in exec-directory.
-		      ;; Bug#31737
-		      (apply
-		       #'call-process
-		       (append
-			(list
-			 mail-source-movemail-program
-			 nil errors nil from to)))))
-	      (when (file-exists-p to)
-		(set-file-modes to mail-source-default-file-modes 'nofollow))
-	      (if (and (or (not (buffer-modified-p errors))
-			   (zerop (buffer-size errors)))
-		       (and (numberp result)
-			    (zerop result)))
-		  ;; No output => movemail won.
-		  t
-		(set-buffer errors)
-		;; There may be a warning about older revisions.  We
-		;; ignore that.
-		(goto-char (point-min))
-		(if (search-forward "older revision" nil t)
-		    t
-		  ;; Probably a real error.
-		  (subst-char-in-region (point-min) (point-max) ?\n ?\  )
-		  (goto-char (point-max))
-		  (skip-chars-backward " \t")
-		  (delete-region (point) (point-max))
-		  (goto-char (point-min))
-		  (when (looking-at "movemail: ")
-		    (delete-region (point-min) (match-end 0)))
-		  ;; Result may be a signal description string.
-		  (unless (yes-or-no-p
-			   (format "movemail: %s (%s return).  Continue? "
-				   (buffer-string) result))
-		    (error "%s" (buffer-string)))
-		  (setq to nil)))))))
+	(save-excursion
+	  (setq errors (generate-new-buffer " *mail source loss*"))
+	  (let ((default-directory "/"))
+	    (setq result
+		  ;; call-process looks in exec-path, which
+		  ;; contains exec-directory, so will find
+		  ;; Mailutils movemail if it exists, else it will
+		  ;; find "our" movemail in exec-directory.
+		  ;; Bug#31737
+		  (apply
+		   #'call-process
+		   (append
+		    (list
+		     mail-source-movemail-program
+		     nil errors nil from to)))))
+	  (when (file-exists-p to)
+	    (set-file-modes to mail-source-default-file-modes 'nofollow))
+	  (if (and (or (not (buffer-modified-p errors))
+		       (zerop (buffer-size errors)))
+		   (and (numberp result)
+			(zerop result)))
+	      ;; No output => movemail won.
+	      t
+	    (set-buffer errors)
+	    ;; There may be a warning about older revisions.  We
+	    ;; ignore that.
+	    (goto-char (point-min))
+	    (if (search-forward "older revision" nil t)
+		t
+	      ;; Probably a real error.
+	      (subst-char-in-region (point-min) (point-max) ?\n ?\  )
+	      (goto-char (point-max))
+	      (skip-chars-backward " \t")
+	      (delete-region (point) (point-max))
+	      (goto-char (point-min))
+	      (when (looking-at "movemail: ")
+		(delete-region (point-min) (match-end 0)))
+	      ;; Result may be a signal description string.
+	      (unless (yes-or-no-p
+		       (format "movemail: %s (%s return).  Continue? "
+			       (buffer-string) result))
+		(error "%s" (buffer-string)))
+	      (setq to nil))))))
       (when (buffer-live-p errors)
 	(kill-buffer errors))
       ;; Return whether we moved successfully or not.