Revert "Don't output tons of messages on apidoc." and "Fix bot breaks."

Revert "Don't output tons of messages on apidoc." and "Fix bot breaks."

This reverts r19662 and r19666.

Committed: https://code.google.com/p/dart/source/detail?r=19694

[ahe, 2013-03-08 12:41:11]

I'm reverting CL 12642004 and CL 12662002.  The changes are incorrect.

Changing a diagnostic from "WARNING" to "VERBOSE_INFO" is a change to whether or
not the compiler follows the Dart language specification.  "VERBOSE_INFO" are
informational messages that should not normally be printed, whereas "WARNING" is
something that is required by the Dart language specification.  This is
documented in
https://code.google.com/p/dart/source/browse/branches/bleeding_edge/dart/sdk/...

If making changes to dart2js that affects how it implements the Dart language
semantics, you're supposed to:

1. Be familiar with the Dart language specification.

2. Include an automated test (unless it is covered by an existing automated test
that start passing).

3. Not rewrite existing tests so that they become incorrect.

Currently the language specification says:

"It is a compile-time error to import two different libraries with the same
name."

So it is actually a bug in dart2js that it is only warning.

In the future, I suggest the following approach when making changes to dart2js:

* Always CC compiler-dev@dartlang.org.

* Wait for a code review from AAR.

[Johnni Winther, 2013-03-08 12:45:13]

lgtm

[ahe, 2013-03-08 13:55:49]

Committed patchset #1 manually as r19694 (presubmit successful).