bug#31245: 27.0.50; Crash in Windows emacs

[Andy Moreton <andrewjmoreton@gmail.com>]

I am seeing occasional crashes in emacs, but am currently unable to
run gdb on my machine at $work.

Decoding emacs_backtrace.txt gives:

w32_backtrace at C:/emacs/git/emacs/master/src/w32fns.c:10645
emacs_abort at C:/emacs/git/emacs/master/src/w32fns.c:10680
bidi_pop_it at C:/emacs/git/emacs/master/src/bidi.c:946
pop_it at C:/emacs/git/emacs/master/src/xdisp.c:6265
next_overlay_string at C:/emacs/git/emacs/master/src/xdisp.c:5662
set_iterator_to_next at C:/emacs/git/emacs/master/src/xdisp.c:7779
move_it_in_display_line_to at C:/emacs/git/emacs/master/src/xdisp.c:9230
move_it_to at C:/emacs/git/emacs/master/src/xdisp.c:9480
partial_line_height at C:/emacs/git/emacs/master/src/xdisp.c:10047
try_window at C:/emacs/git/emacs/master/src/xdisp.c:17759
redisplay_window at C:/emacs/git/emacs/master/src/xdisp.c:17181
redisplay_window_0 at C:/emacs/git/emacs/master/src/xdisp.c:14938
internal_condition_case_1 at C:/emacs/git/emacs/master/src/eval.c:1358
redisplay_windows at C:/emacs/git/emacs/master/src/xdisp.c:14918
redisplay_windows at C:/emacs/git/emacs/master/src/xdisp.c:14912
redisplay_internal at C:/emacs/git/emacs/master/src/xdisp.c:14401
redisplay at C:/emacs/git/emacs/master/src/xdisp.c:13612
read_char at C:/emacs/git/emacs/master/src/keyboard.c:2484
read_key_sequence at C:/emacs/git/emacs/master/src/keyboard.c:9150
command_loop_1 at C:/emacs/git/emacs/master/src/keyboard.c:1370
internal_condition_case at C:/emacs/git/emacs/master/src/eval.c:1330
command_loop_2 at C:/emacs/git/emacs/master/src/keyboard.c:1111
internal_catch at C:/emacs/git/emacs/master/src/eval.c:1099
command_loop at C:/emacs/git/emacs/master/src/keyboard.c:1090
recursive_edit_1 at C:/emacs/git/emacs/master/src/keyboard.c:694
Frecursive_edit at C:/emacs/git/emacs/master/src/keyboard.c:765
main at C:/emacs/git/emacs/master/src/emacs.c:1717
__tmainCRTStartup at 
C:/repo/mingw-w64-crt-git/src/mingw-w64/mingw-w64-crt/crt/crtexe.c:331
mainCRTStartup at 
C:/repo/mingw-w64-crt-git/src/mingw-w64/mingw-w64-crt/crt/crtexe.c:214
__start at C:/emacs/git/emacs/master/src/unexw32.c:111

In GNU Emacs 27.0.50 (build 48, x86_64-w64-mingw32)
Repository revision: 0ecc10a7771bf1f62d15b2e6c747bee9f7a557ff
Windowing system distributor 'Microsoft Corp.', version 10.0.16299

Configured using:
  'configure --prefix=/c/emacs/emacs-master --without-dbus --with-gif
  --with-gnutls --without-imagemagick --with-jpeg --with-json
  --with-lcms2 --with-modules --with-png --without-pop --with-rsvg
  --with-tiff --with-xml2 --with-xpm --enable-checking 'CFLAGS= -g3 -O0
  -gdwarf-4 -fdiagnostics-color=never'
  PKG_CONFIG_PATH=/mingw64/lib/pkgconfig:/mingw64/share/pkgconfig'