fix($parse): remove references to last arguments to a fn call

[vojtajina]

This can be an issue if running (and killing) multiple apps/injectors on the same page. The args array holds references to all previous arguments to a function call and thus they cannot be garbage-collected.

In a regular (one app/injector on a page) app, this is not an issue.

cc @aaronfrost

[petebacondarwin]

If the $parse service was destroyed and rebuilt would that not free up these objects?

[jbedard]

Is there any point keeping the array around if it gets set to a length of 0 each time? Does that still avoid reallocating each time?

[ghost]

Just a note: this issue could have still created memory leaks in a single-injector app when using ng-view.

Passing a function argument refering to the DOM (such as $event) would have caused the DOM reference to be indirectly cached. After switching the view away, its entire DOM would have been leaked, including directives, scopes, etc.