Report HintCode.UNUSED_ELEMENT for classes.

R=brianwilkerson@google.com
BUG=

Review URL: https://codereview.chromium.org//704413005

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41650 260f80e4-7a28-3924-810f-c04153c831b5
Issue 21552. Fixes for navigation, hover and rename in instance creation expressions.

R=brianwilkerson@google.com, paulberry@google.com
BUG= https://code.google.com/p/dart/issues/detail?id=21552

Review URL: https://codereview.chromium.org//717513003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41651 260f80e4-7a28-3924-810f-c04153c831b5
Add parser recovery tests. These correspond to some cases that dart2js is currently handling that I wanted to make sure we also handled.

R=paulberry@google.com

Review URL: https://codereview.chromium.org//703773004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41652 260f80e4-7a28-3924-810f-c04153c831b5