(second try) unittest steps 3, 4: removes TestFramework.dart

(second try) unittest steps 3, 4: removes TestFramework.dart

Committed: https://code.google.com/p/dart/source/detail?r=6980

[Siggi Cherem (dart-lang), 2012-04-25 20:42:45]

I uploaded 2 patch sets, Patch set 1 is the original CL reviewed before. Patch
set 2 contains the new changes (2 lines).

The error was that I assumed [Exception] had a [message] property. This problem
showed only in negative tests that, when they failed in the browser, the browser
threw a second exception trying to print the FAIL error, at that point, selenium
timed out waiting for a reply.

[Bob Nystrom, 2012-04-25 22:19:44]

lgtm