clo_processing is now done when this procedure is called.
So, we can now allocate this memory only when approx history level
is requested.

I double checked using printf that clo processing was done before
this procedure is called.



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13915 a5019735-40e9-0310-863c-91ae7b9d1cf9