Fix: oninput detection for IE9-

The oninput event detection was not as precise in IE9- as it could be. The oninput test was reporting ```undefined``` instead of ```false```, thus making unit tests failing:
* 5. Modernizr classes and bools: html classes are looking good<br>
  Test number **163**: oninput is correctly false in the classes and objectExpected:  false Result:  undefined Diff:  false undefined  
* 6. Modernizr classes and bools: Modernizr properties are looking good<br>
  Test number **283**: Modernizr.oninput is a boolean value or Boolean object

This was caused by fact that events are created and fired differently in IE9-, see respective code change.