Fix operator== and hashCode for File and Folder objects.

Fix operator== and hashCode for File and Folder objects.

This is necessary in order for File and Folder objects to be safely
stored in HashSets and HashMaps.

R=scheglov@google.com

Committed: https://code.google.com/p/dart/source/detail?r=37926

[scheglov, 2014-07-02 00:32:56]

LGTM

https://codereview.chromium.org/345063005/diff/1/pkg/analysis_server/test/res...
File pkg/analysis_server/test/resource_test.dart (right):

https://codereview.chromium.org/345063005/diff/1/pkg/analysis_server/test/res...
pkg/analysis_server/test/resource_test.dart:298: expect(folder == folder2,
isTrue);
Any test for a case when == returns false for memory/physical resources?

[Paul Berry, 2014-07-02 00:37:15]

https://codereview.chromium.org/345063005/diff/1/pkg/analysis_server/test/res...
File pkg/analysis_server/test/resource_test.dart (right):

https://codereview.chromium.org/345063005/diff/1/pkg/analysis_server/test/res...
pkg/analysis_server/test/resource_test.dart:298: expect(folder == folder2,
isTrue);
On 2014/07/02 00:32:56, scheglov wrote:
> Any test for a case when == returns false for memory/physical resources?

Good point.  I'll add those.

[Paul Berry, 2014-07-02 00:46:21]

Committed patchset #1 manually as r37926 (presubmit successful).