Streamline the CPS IR Visitor interface.

pkg/analyzer2dart/test/sexpr_data.dart

Index: pkg/analyzer2dart/test/sexpr_data.dart
diff --git a/pkg/analyzer2dart/test/sexpr_data.dart b/pkg/analyzer2dart/test/sexpr_data.dart
index d380c6d1d358d7cd4c62d070ea7e911dc6cae578..5b35b1b5e45ce3a08252ab5f0fcb98df7bffc376 100644
--- a/pkg/analyzer2dart/test/sexpr_data.dart
+++ b/pkg/analyzer2dart/test/sexpr_data.dart
@@ -1399,7 +1399,8 @@ main() {
     (InvokeConstructor C () k0)))
 ''',
 'C.':  '''
-(FunctionDefinition  () return
+(ConstructorDefinition () return (
+    )
   (LetPrim (v0 (Constant (Null)))
     (InvokeContinuation return (v0))))
 '''}),
@@ -1420,7 +1421,8 @@ main() {
     (InvokeConstructor C () k0)))
 ''',
 'C.': '''
-(FunctionDefinition  () return
+(ConstructorDefinition () return (
+    )
   (LetPrim (v0 (Constant (Null)))
     (InvokeContinuation return (v0))))
 '''}),
@@ -1442,12 +1444,14 @@ main() {
     (InvokeConstructor C () k0)))
 ''',
 'B.':  '''
-(FunctionDefinition  () return
+(ConstructorDefinition () return (
+    )
   (LetPrim (v0 (Constant (Null)))
     (InvokeContinuation return (v0))))
 ''',
 'C.': '''
-(FunctionDefinition  () return
+(ConstructorDefinition () return (
+    )
   (LetPrim (v0 (Constant (Null)))
     (InvokeContinuation return (v0))))
 '''}),
@@ -1469,12 +1473,14 @@ main() {
     (InvokeConstructor C () k0)))
 ''',
 'B.': '''
-(FunctionDefinition  () return
+(ConstructorDefinition () return (
+    )
   (LetPrim (v0 (Constant (Null)))
     (InvokeContinuation return (v0))))
 ''',
 'C.':  '''
-(FunctionDefinition  () return
+(ConstructorDefinition () return (
+    )
   (LetPrim (v0 (Constant (Null)))
     (InvokeContinuation return (v0))))
 '''}),