Make sure the mixin class is finalized immediately (and not some time later)

Make sure the mixin class is finalized immediately (and not some time later)
before applying mixin members (issue 22719).
Add regression test.

R=asiva@google.com

Committed: https://code.google.com/p/dart/source/detail?r=44383

[regis, 2015-03-10 18:23:58]

regis@google.com changed reviewers:
+ asiva@google.com

[regis, 2015-03-10 18:23:58]

This does not address the fact that EnsureIsFinalized() does not immediately
finalize the class. If this is acceptable semantics, it should be specified in a
comment in the header.

[siva, 2015-03-10 18:31:34]

lgtm

I sent you a similar change list, you can ignore my CL :-)

https://codereview.chromium.org/994103002/diff/1/tests/language/regress_22719...
File tests/language/regress_22719_test.dart (right):

https://codereview.chromium.org/994103002/diff/1/tests/language/regress_22719...
tests/language/regress_22719_test.dart:25: print(i);
Change this to an Expect.

[regis, 2015-03-10 18:39:17]

Thanks!

https://codereview.chromium.org/994103002/diff/1/tests/language/regress_22719...
File tests/language/regress_22719_test.dart (right):

https://codereview.chromium.org/994103002/diff/1/tests/language/regress_22719...
tests/language/regress_22719_test.dart:25: print(i);
On 2015/03/10 18:31:34, siva wrote:
> Change this to an Expect.

Done.

[regis, 2015-03-10 18:39:55]

Committed patchset #2 (id:20001) manually as r44383 (presubmit successful).