Encapsulate the helper functions in mjsunit.js.
Now only exposes the exception class and the assertXXX functions.

Make assertEquals use === instead of ==.
This prevents a lot of possiblefalse positives in tests, and avoids
having to do assertTrue(expected === actual) when you need it.

Fixed some tests that were either buggy or assuming == test.

Review URL: http://codereview.chromium.org/6869007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7628 ce2b1a6d-e550-0410-aec6-3dcde31c8c00