It appears that TransmitFile Windows API does not work with Windows
pipes. So just copy data from pipe and into TCP connection manually.

Fixes #22278

Change-Id: I4810caca5345eac5bffb3176956689b8ae993256
Reviewed-on: https://go-review.googlesource.com/79775
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>