Add test to compare-failures

Add test to compare-failures

+ support build group names as command-line argument

R=dmitryas@google.com

Committed: https://github.com/dart-lang/sdk/commit/dc83f621996a14f7238ed8c11ad10cb9d7928722

[Johnni Winther, 2017-08-01 11:14:09]

johnniwinther@google.com changed reviewers:
+ dmitryas@google.com

[Dmitry Stefantsov, 2017-08-01 11:58:32]

These great changes LGTM!

I have one question out of curiosity: is it a good idea to use "pkg:testing"
eventually?  This way we could run all the tests (I hope we'll have plenty of
them!) with one command.

[Johnni Winther, 2017-08-02 07:38:13]

On 2017/08/01 11:58:32, Dmitry Stefantsov wrote:
> These great changes LGTM!
> 
> I have one question out of curiosity: is it a good idea to use "pkg:testing"
> eventually?  This way we could run all the tests (I hope we'll have plenty of
> them!) with one command.

It is. Adding a TODO.

[Johnni Winther, 2017-08-02 07:39:00]

Description was changed from

==========
Add test to compare-failures

+ support build group names as command-line argument
==========

to

==========
Add test to compare-failures

+ support build group names as command-line argument

R=dmitryas@google.com

Committed:
https://github.com/dart-lang/sdk/commit/dc83f621996a14f7238ed8c11ad10cb9d7928722
==========

[Johnni Winther, 2017-08-02 07:39:02]

Committed patchset #1 (id:1) manually as
dc83f621996a14f7238ed8c11ad10cb9d7928722 (presubmit successful).