Adjusted comments on two lines in co19-dart2js.status

Adjusted two tests in co19-dart2js.status

One test was associated with co19 issue 727, which turned out to be
only partially correct; as a consequence issue 21197 is invalid and
was removed from status.  The other test was associated with co19
issue 731, which turned out to be wrong; as a consequence, a new issue
21271 was created and listed in status.

R=ricow@google.com

Committed: https://code.google.com/p/dart/source/detail?r=41120

[eernst, 2014-10-14 16:17:24]

Updates needed because the associated issues were changed.

[ricow1, 2014-10-15 06:32:27]

ricow@google.com changed reviewers:
+ ricow@google.com

[ricow1, 2014-10-15 06:32:28]

Erik: Did you want to add reviewers?
anyway, lgtm

[eernst, 2014-10-15 10:47:25]

Committed patchset #2 (id:20001) manually as 41120 (presubmit successful).