Bug 1070487 - [keyboard] 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 same api chenged 

1. assert.length -> assert.lengthOf
2. in new version assert.deepEqual take prototype into consideration same test need change

this compatible with both old and new version chaijs library
It seems this function has lost its original usage, since rowIndex and enterIndex aren't used anymore.
If that is the case, we should modify the function name.