Screen resolution is unchanged on VM window resize with GA installed (again)

Basically clone of ticket CORE-17896, but a new regression.

• Partially degraded in 0.4.15-dev-4370-g3cb1dd8
• Completely regressed in 0.4.15-dev-4378-ga0cfdcd .. 0.4.15-dev-4380-g2d2824f

Steps to reproduce:

• Install ReactOS BootCD on VirtualBox (tested version 6.1.30)
• Install VirtualBox Guest Additions
• Get to the desktop and maximize or resize VM window
• Expected: Screen size is being adjusted to VM window
• Observed: Screen size is unchanged

It's possible to change screen resolution manually in the Display Properties to make it fit the VM window, just like in the previous ticket.

There is different behaviour on different commits documented below:

• 0.4.15-dev-4369-g21ddeb7 - no regression - 0.4.15-dev-4369-g21ddeb7.txt
  • started in 256 colors (tracked in CORE-18027)
  • on VM window resize - screen size adjusted successfully
  • on VM window restore - adjusted successfully
  • start desk.cpl - set color depth to 32-bit
  • on VM window resize - screen size adjusted successfully
  • on VM window restore - adjusted successfully
• 0.4.15-dev-4370-g3cb1dd8 - partially degraded - 0.4.15-dev-4370-g3cb1dd8.txt
  • started in 256 colors
  • on VM window resize - screen size adjusted successfully
  • on VM window restore - screen size remained the same
  • start desk.cpl - not possible to change screen size after this point
  • start desk.cpl in debug mode - assertion and bug check
  • performed a reboot - set color depth to 32-bit
  • on VM window resize - screen size adjusted successfully
  • on VM window restore - adjusted successfully
• 0.4.15-dev-4378-ga0cfdcd - broken - 0.4.15-dev-4378-ga0cfdcd.txt
  • Assertion FALSE in /win32ss/gdi/eng/pdevobj.h, line 170
• 0.4.15-dev-4380-g2d2824f - regressed - 0.4.15-dev-4380-g2d2824f.txt
  • started in 256 colors
  • on VM window resize - screen size remained the same
  • on VM window restore - screen size remained the same
  • start desk.cpl in normal mode - set color depth to 32-bit
  • start desk.cpl in debug mode - assertion and bug check
  • on VM window resize - screen size remained the same
  • on VM window restore - screen size remained the same
• 0.4.15-dev-4469-g1d66a0a - latest master - 0.4.15-dev-4469-g1d66a0a.txt
  • started in 256 colors
  • on VM window resize - screen size remained the same
  • on VM window restore - screen size remained the same
  • start desk.cpl in normal mode - set color depth to 32-bit
  • start desk.cpl in debug mode - works
  • on VM window resize - screen size remained the same
  • on VM window restore - screen size remained the same

Cc hpoussin for guilty commits.