track alloc counts per callstack for leak diagnosis

From derek.br...@gmail.com on December 10, 2010 17:58:15

PR 514043

for analyzing leaks, reporting the count of allocations from that callstack and the ordinals of the ones that leaked would be useful

then you'd know "ok it's the 53rd instance here that leaked, so it's on some rare path, and from the timetamp (PR 465163) it happened late in the run"

this case includes adding the timestamp to leaks that was added to other errors in PR 465163. we'll have to add it to all stored callstacks which will occupy some space, so we may want it under a runtime option

Original issue: http://code.google.com/p/drmemory/issues/detail?id=173