bug#28915: Emacs 27 under macOS window system; improper frame resizing (off by 4 pixels)

[Bob Weiner]

Each time the following two expressions are called, they increase the
width or height respectively of the selected frame by 4 pixels rather
than leaving the dimension unchanged.  Even if this is a rounding error
due to use of column/line math, shouldn't there be a special case test
for this that prevents the size change?  It would simplify coding.

(progn (set-frame-width nil (frame-pixel-width) nil t)
       (frame-pixel-width))

(progn (set-frame-height nil (frame-pixel-height) nil t)
       (frame-pixel-height))

Bob