wininet: Ensure that we have data to report before sending INTERNET_STATUS_REQUEST_COMPLETE in HTTP_HttpEndRequestW.

It's unused now.

This happened to work because the field offsets are the same.

This way we get correct behavior if the application has depth and stencil related tests
disabled. If we attach the depth stencil GL limits the framebuffer size to the smallest
surface, making some parts of the framebuffer inaccessible.