[PATCH] freetype: Handle failing glyph rendering

[PATCH] freetype: Handle failing glyph rendering

When FT_Render_Glpyh fails the slot returns a bitmap containing a valid
width and height but a null buffer.

When we eventually memcpy this buffer we will crash. Existing error
handling in this method returns null on errors.

Pick-to: 6.10 6.8
Fixes: QTBUG-145310
Change-Id: I4737ab4d769b52f42bd1ef9037c8b9fd681a4ae8
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>
(cherry picked from commit 1b4f4b1797bc7db3eea6ef83a34df61d7bf78e17)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
Gbp-Pq: Name upstream_freetype-handle-failing-glyph-rendering.patch