Don't skip tests on machines without git.

Don't skip tests on machines without git.

R=nweiz@google.com

Committed: https://code.google.com/p/dart/source/detail?r=29490

[Bob Nystrom, 2013-10-29 20:23:28]

This removes the special handling from pub for running tests on machines without
git installed. It used to silently skip tests that required git if you didn't
have it installed (unless it was running on a bot).

Now it fails the test. If you want to run the pub tests, you need git.

[nweiz, 2013-10-29 20:57:10]

lgtm

[Bob Nystrom, 2013-10-29 20:59:38]

Committed patchset #1 manually as r29490 (presubmit successful).

[kustermann, 2013-10-30 00:44:09]

Thank you very much, bob :)