Emit warning on import of dart:mirrors.

BUG=
R=floitsch@google.com

Review URL: https://codereview.chromium.org//588183002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41688 260f80e4-7a28-3924-810f-c04153c831b5
Skip enum_test for dart2analyzer

BUG=

Review URL: https://codereview.chromium.org//721733002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41689 260f80e4-7a28-3924-810f-c04153c831b5
Avoid emmitting is test for Function if superclass already has it.

R=johnniwinther@google.com
BUG=

Review URL: https://codereview.chromium.org//723523003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41690 260f80e4-7a28-3924-810f-c04153c831b5