When AutoScroll = true, Form size become smaller after show and hide

* .NET Core Version: (3.0 Preview8)
* Have you experienced this same bug with .NET Framework?: Yes

**Problem description:**
After click form maximize button serval times, form will be very small.

**Actual behavior:**
form size will reduce 17 unit after click form maximize button twice.

**Expected behavior:**
form size not change after click form maximize button twice.

**Minimal repro:**
create a winform project
drag a control oveflow form
set form AutoScroll = true

Run
click maximize button serval times(over 10 times will be very clear), you will find form become smaller than before.

But AutoScroll = false, this issue can not reproduce.
[WindowsFormsApp3.zip](https://github.com/dotnet/winforms/files/3523495/WindowsFormsApp3.zip)