LocalInitializer lets us to bind temporaries to variables in the
initializer list. We use it to ensure the arguments to super() are
evaluated at the right time.
accessors.dart and the new file super_calls.dart have been moved into
a folder "frontend" for frontend helpers that operate on Kernel IR.
BUG=
R=kustermann@google.com
Review URL: https://chromereviews.googleplex.com/457457013 .
For constructor bodies, we arbitrarily set the return type to 'void'.
Although there is hardly any legitimate use for the "return type" of
a constructor, this doesn't have any overhead and it simplifies the
restriction on FunctionNode.
BUG=
R=kmillikin@google.com
Review URL: https://chromereviews.googleplex.com/446827013 .