Fix crashes in wxDateTime::ParseDate() for some invalid dates.

Parsing an incomplete date with nothing but whitespace and/or date delimiter
characters at the end crashed as we happily went beyond the end of string.

Fix this by not using a loop which didn't check for the iterator validity.

Closes #12685.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66166 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/datetimefmt.cpp

@@ -1625,9 +1625,10 @@ wxDateTime::ParseDate(const wxString& date, wxString::const_iterator *end)
     while ( p != pEnd )
     {
         // skip white space and date delimiters
-        while ( wxStrchr(".,/-\t\r\n ", *p) )
+        if ( wxStrchr(".,/-\t\r\n ", *p) )
         {
             ++p;
+            continue;
         }
 
         // modify copy of the iterator as we're not sure if the next token is