When inlining is being done, it is crucial to use the correct type feedback
oracle with a given type feedback ID. To ensure this, TestContext now carries an
oracle which is associated with the context's condition, and these are both used
together in TestContext::BuildBranch.

Note that in VisitReturnStatement and TryInline we are currently lucky that the
oracles don't go out of sync in an observable way, but this will change when we
inline setters. Therefore, there is no separate test case...

Review URL: https://chromiumcodereview.appspot.com/10834247

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12284 ce2b1a6d-e550-0410-aec6-3dcde31c8c00