tests for dynamic calls to generic functions/methods

[jmesserly]

From @jmesserly on April 28, 2016 20:51

I'll try to add some, but this is the sort of thing that could use exhaustive testing. Likely the other Dart implementations will be able to benefit as well once they implement generic methods.

Copied from original issue: dart-archive/dev_compiler#533

[jmesserly]

this is in much better shape now that generic methods were added to the language, so I think we can close it out.