Typecheck const classes in the context of the constructor call.

pkg/compiler/lib/src/js_backend/constant_handler_javascript.dart

Index: pkg/compiler/lib/src/js_backend/constant_handler_javascript.dart
diff --git a/pkg/compiler/lib/src/js_backend/constant_handler_javascript.dart b/pkg/compiler/lib/src/js_backend/constant_handler_javascript.dart
index 57ae567823919c696797cb2cd53fdff523ff4560..783a19b8b82dabf6be3951452563e69711891f03 100644
--- a/pkg/compiler/lib/src/js_backend/constant_handler_javascript.dart
+++ b/pkg/compiler/lib/src/js_backend/constant_handler_javascript.dart
@@ -118,12 +118,13 @@ class JavaScriptConstantCompiler extends ConstantCompilerBase
 
   ConstantExpression compileVariableWithDefinitions(VariableElement element,
                                           TreeElements definitions,
-                                          {bool isConst: false}) {
+                                          {bool isConst: false,
+                                           bool checkType: true}) {
     if (!isConst && lazyStatics.contains(element)) {
       return null;
     }
     ConstantExpression value = super.compileVariableWithDefinitions(
-        element, definitions, isConst: isConst);
+        element, definitions, isConst: isConst, checkType: checkType);
     if (!isConst && value == null) {
       lazyStatics.add(element);
     }