Tempoarily return 0 from taskkill process. 

We are seeing hanging firefox instances on windows.

Review URL: https://codereview.chromium.org//23809006

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@27229 260f80e4-7a28-3924-810f-c04153c831b5
1 file changed