adb: win32: write ACK to separate pipe instead of stdout

The win32 version of 9f2d1a9c. The big
technique is to fit a Win32 HANDLE value in an int because it only uses
32-bits. This allows most of the other adb code to stay the same.

Also, fix a regression in the 'adb server nodaemon' command that was
erroneously returning an error when --reply-fd was not used, which
should not be necessary for this particular command.

Change-Id: I37e9c609014b813af93bf0d6c12f665b59c93c41
Signed-off-by: Spencer Low <CompareAndSwap@gmail.com>