Fix unparsing of variable definitions.

Fix unparsing of variable definitions.
Example affecting method with method args:
foo(f(arg)){}

would unparse to:
foo(var f(arg)){}

Also correctly unparse variable definition modifiers.

Committed: https://code.google.com/p/dart/source/detail?r=9550

[Anton Muhin, 2012-07-11 13:59:22]

lgtm