Add a test to verify that analysis server code generation is up to date.

Add a test to verify that analysis server code generation is up to date.

This test will run on the Windows, Linux, and MacOS buildbots, so it
should help ensure that code generation works properly on all of those
platforms.

R=jwren@google.com

Committed: https://code.google.com/p/dart/source/detail?r=39201

[jwren, 2014-08-13 14:41:44]

On 2014/08/12 22:59:30, Paul Berry wrote:

LGTM

[Paul Berry, 2014-08-13 15:29:12]

Committed patchset #2 manually as r39201 (presubmit successful).