Fix language/bad_constructor_test in dartk and analyzer.

pkg/kernel/lib/analyzer/ast_from_analyzer.dart

Index: pkg/kernel/lib/analyzer/ast_from_analyzer.dart
diff --git a/pkg/kernel/lib/analyzer/ast_from_analyzer.dart b/pkg/kernel/lib/analyzer/ast_from_analyzer.dart
index cbbf53ea29593bb3c3d1d3e6e6373d64d072a1db..f6830de82b6b9af0fae0bc46f96a2957fe3d1226 100644
--- a/pkg/kernel/lib/analyzer/ast_from_analyzer.dart
+++ b/pkg/kernel/lib/analyzer/ast_from_analyzer.dart
@@ -2738,6 +2738,10 @@ class MemberBodyBuilder extends GeneralizingAstVisitor<Null> {
   }
 
   void buildGenerativeConstructor(ConstructorDeclaration node) {
+    if (currentMember is! ast.Constructor) {
+      buildBrokenMember();
+      return;
+    }
     addAnnotations(node.metadata);
     ast.Constructor constructor = currentMember;
     constructor.function = scope.buildFunctionNode(node.parameters, node.body,
@@ -2790,6 +2794,10 @@ class MemberBodyBuilder extends GeneralizingAstVisitor<Null> {
   }
 
   void buildFactoryConstructor(ConstructorDeclaration node) {
+    if (currentMember is! ast.Procedure) {
+      buildBrokenMember();
+      return;
+    }
     addAnnotations(node.metadata);
     ast.Procedure procedure = currentMember;
     ClassElement classElement = resolutionMap