Bug 1070845 - [sharedtest] unit test refactoring for new version chai.assert api

test_agent used very old version chai library version=0.5.3
in the current version=1.9.1 deepEqual take prototype into consideration
 this real misprint!!
in new version chai i have fail test with strange messages with negative  outputHeight - this message from other function 

this argument test will positive!!

Mon, 22 Sep 2014 05:47:51 -0700 от Julien Wajsberg <notifications@github.com>:
>In shared/js/image_utils.js:
>> @@ -270,7 +270,7 @@
>                                               outputType)
>    {
>      if (!outputWidth || !isFinite(outputWidth) || outputWidth <= 0 ||
> -        !outputHeight || !isFinite(outputHeight || outputHeight <= 0)) {
> +        !outputHeight || !isFinite(outputHeight) || outputHeight <= 0) {
>does not look chai related but looks to be a real issue... what do you think  @davidflanagan
>—
>Reply to this email directly or  view it on GitHub .

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