fix(inputs): ignoring input events in IE caused by placeholder changes o...

...r focus/blur on inputs with placeholders

This is my attempt at fixing #8242 as well as the extra placeholder issues with focus/blur. I'm assuming I'm missing a weird test case that still breaks somewhere, but I still think this is an improvement (it definitely is for my use cases).
I wrote a plunker on the MS feedback site which illustrates a variety of cases where we do get an input event when it's not expected (click, which is basically focus --- I don't think we really need to care about blur but why not), and when the attribute changes (regardless of whether there is a value or not).

So we're going to get the input event anyways here