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

This reverts commit aea654b84713b8085ee0a291e3325b1ca53080aa.

Follow-up commit will fix the issue.

Task-number: QTBUG-18852
Task-number: QTBUG-27266
Change-Id: Iadbae6b94de6e47e0b9bf428f57b63ffa286e382
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
Task-number: QTBUG-18852
Change-Id: I33ce3a659a234cb04d3b5ae9d668d193d681be7f
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
(cherry picked from qtbase/54f1d7e2e48b896755aa930ee7e4ecacf51bf977)