MINOR: memprof: report the delta between alloc and free on realloc()

realloc() calls are painful to analyse because they have two non-zero
columns and trying to spot a leaking one requires a bit of scripting.
Let's simply append the delta at the end of the line when alloc and
free are non-nul.

It would be useful to backport this to 2.4 to help with bug reports.
1 file changed