Fix format specifiers used for event logging in the listctrl sample.

Don't use "%ld" for int argument (this is harmless but unnecessary) and cast
wxUIntPtr to long before using it with "%ld" as otherwise its size is greater
than that of long in Win64 builds.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@75145 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775