Skip language/large_class_declaration_test in debug mode on the vm

This is flaky timing out on several platforms, and is consistentnly timing out on our win32 debug russian bot

Review URL: https://codereview.chromium.org//642813010

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41139 260f80e4-7a28-3924-810f-c04153c831b5
Mark the analyzer tests slow generally on dart2js

We are seeing these flake on several bots

Review URL: https://codereview.chromium.org//645063003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41140 260f80e4-7a28-3924-810f-c04153c831b5