bug#53729: 29.0.50; Tamil text not shaped in modeline

[Visuwesh]

Tamil text is not shaped properly in the modeline.  Please view the
attached file "Noto_Serif_modeline.jpg" to see what I mean.  I set
"tamil" script to use "Noto Serif Tamil" in the default fontset like so,

    (set-fontset-font "fontset-default" 'tamil '("Noto Serif Tamil" . 
"iso10646-1"))

Changing the font to "Lohit Tamil" [1] does not fix the shaping issue so
Noto Serif Tamil is not the problem (See file
"Lohit_Tamil_modeline.png").

As shown in "Noto_Serif_Expected.png", the text is shaped as I would
expect, in the minibuffer.

To see if this was specific to Tamil, I tried creating a buffer named
"मेरा" and "नमस्कार" ("mera" and "namaskaar C-b DEL" in devanagari-itrans)
but they are shaped better (but not the same as in-buffer text).  I also
set "devanagari" script to use "Noto Serif Devanagari" in the default
fontset.

I also see the problem in a GTK3 build of Emacs 27.2 (sorry, I do not
have the time to check Emacs 28 or Emacs 29 GTK3, PGTK build right now).

1. https://releases.pagure.org/lohit/lohit-tamil-ttf-2.91.3.tar.gz

Noto_Serif_Expected.png
Description: Expected text shaping

Noto_Serif_modeline.png
Description: Text shaping in modeline with Noto Serif

Lohit_Tamil_modeline.png
Description: Lohit Tamil in modeline

Devanagari.png
Description: Devanagari in modeline

In GNU Emacs 29.0.50 (build 1, x86_64-pc-linux-gnu, X toolkit, cairo version 
1.16.0, Xaw scroll bars)
Repository revision: 58bb9eb4005599155a8fce8d5c5beb531a72c534
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12013000
System Description: NixOS 21.11 (Porcupine)

Configured using:
 'configure
 --prefix=/nix/store/0m0yw7b3zly74ljs3qmkblb780xg03id-emacs-git-20220130.0
 --disable-build-details --with-modules --with-x-toolkit=lucid
 --with-xft --with-cairo --with-native-compilation'

Configured features:
CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG JSON
LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES NATIVE_COMP NOTIFY
INOTIFY PDUMPER PNG RSVG SECCOMP SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS X11 XDBE XIM XPM LUCID ZLIB

Important settings:
  value of $EMACSLOADPATH: 
  value of $EMACSNATIVELOADPATH: 
/nix/store/07cbjwzil3jfhyifj15h60k7yvixzqxs-emacs-packages-deps/share/emacs/native-lisp::
  value of $LANG: en_GB.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Group

Minor modes in effect:
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Load-path shadows:
/home/viz/.nix-profile/share/emacs/site-lisp/site-start hides 
/nix/store/07cbjwzil3jfhyifj15h60k7yvixzqxs-emacs-packages-deps/share/emacs/site-lisp/site-start
/home/viz/lib/emacs/straight/build/map/map hides 
/nix/store/0m0yw7b3zly74ljs3qmkblb780xg03id-emacs-git-20220130.0/share/emacs/29.0.50/lisp/emacs-lisp/map
/home/viz/lib/emacs/straight/build/let-alist/let-alist hides 
/nix/store/0m0yw7b3zly74ljs3qmkblb780xg03id-emacs-git-20220130.0/share/emacs/29.0.50/lisp/emacs-lisp/let-alist

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cl-preloaded nadvice button loaddefs faces cus-face macroexp files
window text-properties overlay sha1 md5 base64 format env code-pages
mule custom widget keymap hashtable-print-readable backquote threads
dbusbind inotify dynamic-setting system-font-setting font-render-setting
cairo x-toolkit x multi-tty make-network-process native-compile emacs)

Memory information:
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