This is yet another very simple code removal from GHOST_WindowWin32.cpp. Why?

Until D10469 blender window creation included code that clamped window locations to within the dimensions of the monitor. But a monitor to the left of your main one will have negative values while those to the right of your main monitor will have bounds that are all greater than the width the monitor it is on. So we might have wanted to place a window at position -1000, 200 but that would get clamped to 0,200.

With the above in place, all new windows would have been always created on the main monitor. So there has always been some code to force children to be on, or relative to, their parents. But with the above fixed that is not longer needed nor desired. So this just removes all uses of the window's parent's bounds as they are never needed.

With this patch applied, you can have one instance of Blender with windows all all over your separate monitors, save the blend file, then reopen and have all the windows restored to where they were. And when when any of those windows open their own children they are (of course) placed correctly.