Avoid save-match-data for efficiency

The functions markdown-cur-line-blank-p and markdown-new-baseline-p
are called repeatedly for font lock and so efficiency is important.
We rarely care about preserving the match data when calling these
functions, so we no longer guarantee that the match data will be
preserved for performance reasons.

markdown-mode.el

@@ -1502,7 +1502,7 @@ region to refontify."
          ;; If the current line has sufficient indentation, mark out pre block
          ;; The opening should be preceded by a blank line.
          ((and (looking-at pre-regexp)
-               (markdown-prev-line-blank-p))
+               (save-match-data (markdown-prev-line-blank-p)))
           (setq open (match-beginning 0))
           (while (and (or (looking-at pre-regexp) (markdown-cur-line-blank-p))
                       (not (eobp)))
@@ -2399,10 +2399,9 @@ in XEmacs 21."
 
 (defun markdown-cur-line-blank-p ()
   "Return t if the current line is blank and nil otherwise."
-  (save-match-data
-    (save-excursion
-      (beginning-of-line)
-      (re-search-forward "^\\s *$" (line-end-position) t))))
+  (save-excursion
+    (beginning-of-line)
+    (re-search-forward "^\\s *$" (line-end-position) t)))
 
 (defun markdown-prev-line-blank-p ()
   "Return t if the previous line is blank and nil otherwise.
@@ -2474,12 +2473,11 @@ Return nil if the current line is not the beginning of a list item."
   "Determine if the current line begins a new baseline level."
   (save-excursion
     (beginning-of-line)
-    (save-match-data
-      (or (looking-at markdown-regex-header)
-          (looking-at markdown-regex-hr)
-          (and (null (markdown-cur-non-list-indent))
-               (= (markdown-cur-line-indent) 0)
-               (markdown-prev-line-blank-p))))))
+    (or (looking-at markdown-regex-header)
+        (looking-at markdown-regex-hr)
+        (and (null (markdown-cur-non-list-indent))
+             (= (markdown-cur-line-indent) 0)
+             (markdown-prev-line-blank-p)))))
 
 (defun markdown-search-backward-baseline ()
   "Search backward baseline point with no indentation and not a list item."