build: improve vcbuild.bat

* Support running multiple test suites (e.g. vcbuild test-simple test-gc).
* Removed a nonexisting test suite (test-uv).
* Removed superfluous extra layer of argument parsing.
* Fix the node-weak build.

R=@rvagg

PR-URL: https://github.com/iojs/io.js/pull/998


Reviewed-By: Rod Vagg <rod@vagg.org>