* lisp/isearch.el: Fix corner cases of isearch-lazy-count.

* lisp/isearch.el: Fix corner cases of isearch-lazy-count.

* lisp/isearch.el (isearch-mode): Reset isearch-lazy-count-current
and isearch-lazy-count-total to nil, so when isearch-mode is started,
there should be no counts from previous Isearch.
(isearch-lazy-highlight-new-loop): Call isearch-message after resetting
lazy-count variables only when isearch-mode is started.  This avoids
the problem of inappropriate calls of isearch-message-function
when query-replace in the minibuffer performs lazy-highlighting that
used to call minibuffer-history-isearch-message unnecessarily.