Fix and Re-enable some unit tests on dialog, tooltip, and draggable

While working on one of my own modules that extends dialogs, I wanted to validate existing dialog tests passed and realized they were disabled in grunt/phantomjs out of the box.

When looking deeper, it seems the main reason my have been the tiny viewportSize phantomjs starts out with causing some of the issues.  A PR to https://github.com/gruntjs/grunt-lib-phantomjs/pull/21 adds the ability to change the viewport directly from the config.  I know the tests won't pass in your CI until this is fixed, but I wanted to record this PR just so I didn't forget about them.  Alternatively, I could have included alternate phantomjs/main.js and a phantomScript option, but that didn't seem like the best option.

Note, I do have questions about the fixes I did here (https://github.com/bdowling/jquery-ui/compare/jquery:master...master#diff-1b4b30b16776f6b3f0a4f05ddfbeb518R561)..  Not sure why ```$(":focus")``` differs from ```document.activeElement```  in these instances in phantomjs, but I don't think changing this impacts what is being tested here.  Perhaps a separate test that should be included in jQuery itself?