bug#46827: Broken initial size of GTK3 frame

[Juri Linkov]

> It's due to to the fact that WM notifications about new frame sizes may
> be processed earlier or later.  I tried to fix that behavior in commit
> a190b4cfd8b6f42a91678ac7292e1cceccd168e7 by having adjust_frame_size
> pick up such notifications on the fly and am closing this bug.

Unfortunately, this commit caused a regression: now there is distracting
blinking of the frame that looks like the visual effect of visible-bell
when it flashes the frame to represent a bell.

This problem can be reproduced only in Gnus.  With such configuration:

  (push '("\\`\\*Summary .*\\*\\'" .
          (display-buffer-in-tab
           (tab-name . "*Summary*")))
        display-buffer-alist)

opening a Gnus group in a new tab flashes the whole frame where empty space
instead of the frame content is visible for a short time.

This problem can't be reproduced with just creating a new tab,
it only manifests in Gnus, maybe something in gnus-summary-read-group-1
with gnus-configure-windows forces frame redisplay or something like this.

This problem doesn't exist without recent changes in a190b4cfd8.