Fix search for item by text in wxMSW wxListCtrl.

Fix search for item by text in wxMSW wxListCtrl.

LVN_ODFINDITEM handler could enter infinite loop if its selection was 0 and a
key not matching any of the items first letters was pressed.

Rewrite the loop in a simpler form to ensure that it is correct. Also clarify
some comments. Finally, fix the behaviour when no matching item was found (if
it didn't hang in infinite loop, it used to select the first item in the
control).

Closes #13026.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67155 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775