Fix ./tool new-test path/to/test
Fix ./tool new-test path/to/test

Summary:
You can run `./tool new-test path/to/test` which will create `newtests/path/to/test/test.js`. The single import statement had a hardcoded relative path which assumed that `test.js` was at `newtests/foo/test.js`. This fixes
Closes https://github.com/facebook/flow/pull/2037

Reviewed By: mroch

Differential Revision: D3522099

Pulled By: gabelevi

fbshipit-source-id: 3d1257cfb159c2431b80cbda09231b9c11ea525f

jgrund/flow,popham/flow,AgentME/flow,jdelStrother/flow,samwgoldman/flow,ylu1317/flow,chenglou/flow,jdelStrother/flow,jamesgpearce/flow,AprilArcus/flow,mroch/flow,AgentME/flow,jgrund/flow,claudiopro/flow,facebook/flow,gabro/flow,samwgoldman/flow,ForbesLindesay/flow,mroch/flow,gabelevi/flow,AgentME/flow,JonathanUsername/flow,gabelevi/flow,MichaelDeBoey/flow,claudiopro/flow,samwgoldman/flow,jeffmo/flow,gabelevi/flow,jeffmo/flow,ForbesLindesay/flow,chenglou/flow,AprilArcus/flow,nmote/flow,ForbesLindesay/flow,gabro/flow,jgrund/flow,facebook/flow,gabelevi/flow,ylu1317/flow,jamesgpearce/flow,claudiopro/flow,mroch/flow,popham/flow,mroch/flow,nmote/flow,ForbesLindesay/flow,JonathanUsername/flow,samwgoldman/flow,TiddoLangerak/flow,TiddoLangerak/flow,fletcherw/flow,jeffmo/flow,JonathanUsername/flow,jgrund/flow,mroch/flow,popham/flow,jdelStrother/flow,TiddoLangerak/flow,jgrund/flow,nmote/flow,samwgoldman/flow,samwgoldman/flow,jamesgpearce/flow,gabelevi/flow,jeffmo/flow,nmote/flow,AprilArcus/flow,ylu1317/flow,claudiopro/flow,nmote/flow,popham/flow,fletcherw/flow,fletcherw/flow,facebook/flow,chenglou/flow,TiddoLangerak/flow,TiddoLangerak/flow,ylu1317/flow,ylu1317/flow,JonathanUsername/flow,facebook/flow,facebook/flow,samwgoldman/flow,chenglou/flow,MichaelDeBoey/flow,fletcherw/flow,jdelStrother/flow,gabelevi/flow,MichaelDeBoey/flow,gabro/flow,jeffmo/flow,mroch/flow,gabro/flow,jdelStrother/flow,AgentME/flow,JonathanUsername/flow,jdelStrother/flow,jamesgpearce/flow,MichaelDeBoey/flow,jgrund/flow,nmote/flow,jamesgpearce/flow,facebook/flow,MichaelDeBoey/flow,AprilArcus/flow,AgentME/flow,gabelevi/flow,AprilArcus/flow,fletcherw/flow,chenglou/flow,popham/flow,popham/flow,jamesgpearce/flow,JonathanUsername/flow,JonathanUsername/flow,jeffmo/flow,jamesgpearce/flow,popham/flow,nmote/flow,facebook/flow,gabro/flow,claudiopro/flow,fletcherw/flow,ForbesLindesay/flow,ForbesLindesay/flow,mroch/flow,gabro/flow,AprilArcus/flow,chenglou/flow