[cfe][InternalNodes] Use internal/external helpers to create AST nodes

This replaces the creation of many AST nodes with calls to either the internal or external helpers, to help enforce passing of needed arguments, in particular file offset which are generally not required.

Change-Id: Id9b2449f398492dd5fb8bf0c71fbe3ec04444c95
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/497842
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>

pkg/kernel/lib/src/ast/expressions.dart

@@ -1550,7 +1550,7 @@ class Arguments extends TreeNode {
       positional = <Expression>[],
       named = <NamedExpression>[];
 
-  factory Arguments.forwarded(FunctionNode function, Library library) {
+  factory Arguments.forwarded(FunctionNode function) {
     return new Arguments(
       function.positionalParameters
           .map<Expression>((p) => new VariableGet(p))