bug#28391: line-pixel-height works at bol but not at eol

[Tak Kunihiro]

When point is at the end of line with an inline image,
line-pixel-height returns height of text instead of that of image.  I
wonder if following response is because of bug or spec.

GNU Emacs 25.2.1 (x86_64-w64-mingw32)
emacs -Q
M-x about-emacs
M-x beginning-of-buffer
M-: (line-pixel-height) => 188
M-x move-end-of-line
M-: (line-pixel-height) => 22

-- Function: line-pixel-height
    This function returns the height in pixels of the line at point in
    the selected window.  The value includes the line spacing of the
    line (*note Line Height::).