Revert "Disable precision timers when running MSVC2012 code on pre-Windows 8."

This reverts commit aa1b4c0943187d82e0c313b93559e99226a9c75a.

It turns out that the bug is caused by a different mask constant
in Windows 8 which should not take effect in pre-Windows 8.

Change-Id: I1ad502262dae42856c07d48ee3bc9dc032ab379b
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Use correct mask constant in the Windows event dispatcher.

Mask out QS_TOUCH, QS_POINTER when running a VS2012-compiled binary
on pre-Windows 8 systems.

Task-number: QTBUG-32257
Task-number: QTBUG-28513
Task-number: QTBUG-29097
Task-number: QTBUG-29435
Change-Id: I33ce3a659a234cb04d3b5ae9d668d193d681be7f
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>