Detach QEventPoint instances during touch compression; test & docs

If we don't detach, they could be modified between the time that the
event is stored (delayed) until it's delivered.

QQuickDeliveryAgentPrivate::compressTouchEvent() had no explicit test
coverage until now; in fact, most tests call QQuickTouchUtils::flush()
after every touch event to ensure that it gets delivered immediately.

Also add internal docs.

Fixes: QTBUG-97185
Fixes: QTBUG-98486
Fixes: QTBUG-98543
Change-Id: I6fd76651ca6fbf15169c44d4d9dbbeb7dc7e3a71
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>
(cherry picked from commit d08038ba7015dc681c95654f7fe5e54b60c2e55c)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

0 files changed, 0 insertions, 0 deletions