Replace const by constexpr when the value of the variable can be
calculated at compile-time.
Fixes: QTBUG-108859
Pick-to: 6.5
Change-Id: I4abf5162d521fc5dca0286a6254f86c57a473367
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
(cherry picked from commit c4a1c171a3b2ade21a344de99962b3848e4ad85a)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>