Harfbuzz-NG: Compile on WinRT

There is no environment (like WinCE) and the basic version
of InitializeCriticalSection is unsupported.

Change-Id: I7c5038115f0dbfdc616bce89a9be166b5f2a1dcc
Reviewed-by: Andrew Knight <andrew.knight@digia.com>
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
winrt: Remove depth/stencil from the default window format

After the last ANGLE upgrade, some hardware fails to render proper
QtQuick scenes when using a depth buffer (which is present in the default
window format). As the batched renderer no longer requires a depth
buffer, this workaround can be safely applied.

Task-number: QTBUG-40649
Change-Id: Id0f6e418aa5c6346186678728f88a6c18af5fb74
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@digia.com>
Remove QPlatformScreenPageFlipper.

Use of this was removed from QtWayland quite a long time ago, which was the only
public user of this API.

Furthermore, it isn't easily possible to implement any use of this API without
full control of the graphics stack (a very rare occurrence) and there is no
public demonstration of this.

There is ongoing research to provide a better replacement for this in the form
of QPlatformHardwareCompositor.

Change-Id: I80d666a5b465aa80f73fed6c44838ce7210bbd30
Reviewed-by: Andrew Knight <andrew.knight@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>