tst_QKeyEvent: Fix MSVC warning about 64bit shift.

tst_qkeyevent.cpp(140): warning C4334: '<<': result of 32-bit shift implicitly converted to 64 bits (was 64-bit shift intended?)

Change-Id: Id3e0eea125f7f7ec13f9b9428e034b922d2ce204
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@theqtcompany.com>