QElapsedTimer/Win: Fix 64-bit integer overflow

QElapsedTimer/Win: Fix 64-bit integer overflow

The ticksToNanoseconds function in qelapsedtimer_win.cpp multiplies
ticks from performance counter with 1000000000 which can sometimes
result in 64-bit integer overflow. This can cause the elapsed time to
reset or jump around.

Task-number: QTBUG-23150
Change-Id: I464503e03cbe64e13906e773beafbf88e7dc256a
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit f30a91ba9d98de1a0ebee5608ba289ac35871a8c)