Remove obsolete backward compatibility kludge

`font-lock-flush' and `font-lock-ensure' were added ten
years ago in Emacs 25.1.  We already depend on Emacs 25.1.

emacsql.el

@@ -378,14 +378,10 @@ Each column must be a plain symbol, no expressions allowed here."
            (sql-mode)
            (with-no-warnings ;; autoloaded by previous line
              (sql-highlight-sqlite-keywords))
-           (if (and (fboundp 'font-lock-flush)
-                    (fboundp 'font-lock-ensure))
-               (save-restriction
-                 (widen)
-                 (font-lock-flush)
-                 (font-lock-ensure))
-             (with-no-warnings
-               (font-lock-fontify-buffer)))
+           (save-restriction
+             (widen)
+             (font-lock-flush)
+             (font-lock-ensure))
            (emacsql--indent)
            (buffer-string))))
     (with-current-buffer (get-buffer-create emacsql-show-buffer-name)