Win32: Use native monitor zoom for menu item image scaling

On Win32, the OS paints MenuItem images using sizes defined by
SM_CXMENUCHECK / SM_CYMENUCHECK. If images are not provided at these
metrics-specific sizes, Windows rescales them, causing unexpected sizes
and alpha channel issues.

In getMenuItemIconSelectedBitmapHandle, adaptZoomForMenuItem was called
which returns a fixed scaled value from getZoom() when fix autoScale
value is provided e.g. 250 instead of the current
monitor's native zoom (150). This caused the OS to perform additional
scaling.

Updated code to call adaptZoomForMenuItem(nativeZoom, image) so that the
image is prepared for the actual monitor zoom, avoiding unnecessary OS
scaling and preserving alpha channel integrity.

Author: ShahzaibIbrahim

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/MenuItem.java

@@ -896,7 +896,7 @@ private long getMenuItemIconBitmapHandle(Image image) {
 		return 0;
 	}
 	if (hBitmap != 0) OS.DeleteObject (hBitmap);
-	int zoom = adaptZoomForMenuItem(getZoom(), image);
+	int zoom = adaptZoomForMenuItem(nativeZoom, image);
 	return Display.create32bitDIB (image, zoom);
 }
 
@@ -906,7 +906,7 @@ private long getMenuItemIconSelectedBitmapHandle() {
 		return 0;
 	}
 	if (hBitmapSelected != 0) OS.DeleteObject (hBitmapSelected);
-	int zoom = adaptZoomForMenuItem(getZoom(), image);
+	int zoom = adaptZoomForMenuItem(nativeZoom, image);
 	return hBitmapSelected = Display.create32bitDIB (image, zoom);
 }