build,win: restore vcbuild TAG functionality

Ref: https://github.com/nodejs/node/pull/17299 Ref: https://github.com/nodejs/abi-stable-node/issues/289

/cc @refack @digitalinfinity @mhdawson

Would someone mind testing this on a Windows machine please?

something like this (off the top of my head, I don't have a Windows machine to tinker with right at this moment):

set DISTTYPE=nightly
set DATESTRING=20180108
set COMMIT=abc123
vcbuild.bat build x64