heap.png issue

[Septyem]

During debug, I find something inconsistent when referring to this flow graph of heap.

It seems the "Yes/No" option in the first branch of SYSMALLOC should be swapped, according to glibc source. https://github.com/lattera/glibc/blob/master/malloc/malloc.c#L2279 （This glibc version is old. But just for reference）