Old taskmgr leaks ~ 4kb per second in Task Manager performance tab

This is a follow up to CORE-18014 - pseudo-memory leak of ~ 4kb per second, observable in taskmgrs performance tab, triggered by the heap.c changes.

After the commit of 0.4.16-dev-1276-g 70732b0, it is no longer happening, but the base issue is NOT fixed, but only a workaround has been committed. I am opening this to contain more details about the problem in hopes of eventually getting to a good solution. Here is a copy of the previous taskmgr for testing purposes.
taskmgr.exe

More details to follow.