bug#55672: 29.0.50; Emacs crashes when calling start-process-shell-command xdg-open with process-connection-type set to nil

[Ihor Radchenko]

> That's a BadGlyph error from a RenderAddGlyphs request, which Emacs does
> not make itself.  What happens if you delete this part of xterm.c?

>  #if defined USE_XCB && defined USE_CAIRO_XCB
>  #define USE_CAIRO_XCB_SURFACE
>  #endif

When I remove these lines, Emacs no longer crashes. However, the behavior is still not right. I can still see flickering (frames being created and immediately closed). I recorded a screencast demonstrating the issue: https://0x0.st/oBHO.mkv