Bluetooth Windows: fix segfault in COM de-init

While doing COM initialization/deinitialization, we always implicitly
assumed that QCoreApplication instance is available.
However, if the Bluetooth objects are re-parented to the main
application, the QCoreApplication instance will already be removed by
the time we want to delete the Bluetooth object (and call COM de-init).

Fix it by caching the main application's thread, and using it instead
of QCoreApplication::instance()->thread() in the mainThreadCoUninit()
helper method.

This commit still assumes that all Bluetooth objects are created
*after* the main QCoreApplication instance.

Amends 340b84a5578f78d7a399e369e900ac991d9e0da2.

Fixes: QTBUG-119063
Pick-to: 6.6 6.5 6.2
Change-Id: I450e4e14039ca27fcfd1f3f131789b049e1edb03
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>
(cherry picked from commit f762e9b646e240d9e8d3d7de928ae1333227c8a0)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

0 files changed, 0 insertions, 0 deletions