bug#64812: 29.1; Setting the default face height on startup only sometimes resizes the frame

[Jim Porter <jporterbugs@gmail.com>]

Normally, when starting Emacs and setting the default face size, Emacs 
will resize the frame so it still has the same number of columns. On 
29.1, this sometimes works that way, but other times the frame pops back 
to its original pixel size. To see this in action, try running the 
following:

emacs -Q --eval "(progn (tool-bar-mode -1) (menu-bar-mode -1) 
(set-face-attribute 'default nil :height 90))"

You might need to try this a few times before the bug happens. (The 
'tool-bar-mode' and 'menu-bar-mode' calls above might not be strictly 
necessary, but they seem to make the issue happen more frequently for 
me.) Even when it does work, I notice that the frame's size bounces back 
and forth a couple of times before settling.

When I test this on 28.2, the frame starts out at its initial size, and 
then shrinks exactly once to the new, slightly smaller size.

I'm seeing this on a GNU/Linux system using X with the default 
configuration, building revision 906ecf442c43da98e6b8c7488f549691901690e9.

(Sorry for only noticing this when testing the release candidate; I 
normally run the development version of Emacs in a terminal, so I didn't 
encounter this issue until doing some final tests of the RC. It's also 
possible there's just something messed up on my system, though Emacs 
28.2 does behave properly...)