Enable mirrors for all the classes in the analyzer tests.

Enable mirrors for all the classes in the analyzer tests.

Othewise dart2js cannot find these classes.

I've tried to annotate *Test classes only with ReflectiveTestCase, but
practically, because almost all the methods are test_*, we end up
having reflection information for almost all methods. So, for simplicity
let's just enable it for everything.


R=brianwilkerson@google.com
BUG=

Committed: https://code.google.com/p/dart/source/detail?r=40980

[Brian Wilkerson, 2014-10-07 21:10:27]

LGTM

[scheglov, 2014-10-07 21:18:50]

Committed patchset #1 (id:1) manually as 40980 (presubmit successful).