fix(input): don't apply textInput to <input type="file">

textInput shouldn't be applied to file inputs to ease writing of custom file input directives.

This change prevents file inputs from instantiating the text input parser/formatter pipelines.

Closes angular#6247
Closes angular#6231

Author: twhitbeck

src/ng/directive/input.js

@@ -424,7 +424,8 @@ var inputType = {
   'hidden': noop,
   'button': noop,
   'submit': noop,
-  'reset': noop
+  'reset': noop,
+  'file': noop
 };
 
 // A helper function to call $setValidity and return the value / undefined,