Revert "Address Peter's comments on Function.apply."

Revert "Address Peter's comments on Function.apply."

This reverts commit 13416.

Committed: https://code.google.com/p/dart/source/detail?r=13417

[floitsch, 2012-10-09 15:30:22]

TBR.

Unbreaks build.

[ahe, 2012-10-09 15:30:41]

LGTM!

[ngeoffray, 2012-10-09 15:54:56]

Thanks Florian

[ngeoffray, 2012-10-09 16:07:18]

Peter: the reason it failed is because the applyFunction is always being
enqueued because it is in js_helper.dart. Therefore, the apply functionality was
always compiled (and it does not support the old specification for optional
parameters). 

I'm open to suggestions on how to avoid calling ensureResolved on the function
class, that doesn't require having two indirections (Function.apply calls
top-level method, calls js helper).