This reverts commit 391b8a3. This causes problems on unix when running the tests, which is much more common. The test runner needs to probably just be redone in a better way. It's old and janky, and has been ported from bash to js, but ought to be replaced with something that exercises npm's functionality in a more proper way.
This is necessary on Windows; otherwise you get 2> 'c:\PROGRAM' is not recognized as an internal or external command, 2> operable program or batch file. since Node/npm are in "C:\Program Files (x86)\nodejs", which has spaces in it.