[REG 5.6.2 -> 5.6.3]: QtWebEngine requires 64 bit host in windows

At the moment we cannot get binaries for QtWebEngine from '5.6' branch for 32 bit windows because webengine compilation needs 64 bit host.

from log:

"Qt WebEngine on Windows must be built on a 64-bit machine.
Qt WebEngine on Windows must be built on a 64-bit machine.
QtWebEngine will not be built."

build log:

https://testresults.qt.io/coin/api/results/qt/qtwebengine/35eda5d8fe78501a075622463f188453dd01af78/WindowsWindows_8_1x86WindowsWindows_8_1x86MSVC2013qtci-windows-8-x86-2-754618DebugAndRelease_Release_OpenGLDynamic/4958d4a48c779c4759ac2d2309da51c0b891d71/build_1502434517/buildlog.txt.gz