Clean up test_runner Command subclass hash/equality.

BUG=
R=ricow@google.com

Review URL: https://codereview.chromium.org//645533002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41037 260f80e4-7a28-3924-810f-c04153c831b5
improve suggestion filtering

BUG=
R=scheglov@google.com

Review URL: https://codereview.chromium.org//644893002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41038 260f80e4-7a28-3924-810f-c04153c831b5
suppress suggestions in string literals

BUG=
R=scheglov@google.com

Review URL: https://codereview.chromium.org//643803002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41039 260f80e4-7a28-3924-810f-c04153c831b5
(TBR) fix the build

BUG=

Review URL: https://codereview.chromium.org//643923002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41040 260f80e4-7a28-3924-810f-c04153c831b5