Form Layout (control size) bug with Anchor = Top | Bottom

* .NET Core Version: all up to 6.0 rc2

* Have you experienced this same bug with .NET Framework?: Yes

**Problem description:**
Form, with any control and `Anchor = AnchorStyles.Top | AnchorStyles.Bottom`.
1. Remember form size and distance from bottom of this control to the bottom of the form.
2. Resize the form that this control become off-screen (if any part of the control still be visible - all work as expected).
3. Add any new control to the form (press `A` key in repro project below).
4. Resize form back to dimensions you remembered on step 1. And see that distance from bottom of the control to the bottom of the form is changed.

https://user-images.githubusercontent.com/17767561/138507989-b39e3f65-96b3-4385-abbc-8f2fa42f2a42.mp4

**Expected behavior:**
Distance from bottom of the control to the bottom of the form must be constant.

I think that the problem is that when new control added, new layout performs from scratch and therefore can't properly process the control with zero height and location outside of the current form dimensions. You can even emulate this in designer:

https://user-images.githubusercontent.com/17767561/138549216-991c7253-80c5-42ca-a049-4b66bc2a5a86.mp4

In the first time it's absolutely reasonable - no way to do this *right*. But I am wonder, if we already have properly align, is it possible not to reset it on `Layout`?

**Minimal repro:**
[FormLayoutBug.zip](https://github.com/dotnet/winforms/files/7400787/FormLayoutBug.zip)