Throw a runtime error when trying to call a constructor of a class that could not be resolved.

lib/compiler/implementation/lib/js_helper.dart

Index: lib/compiler/implementation/lib/js_helper.dart
diff --git a/lib/compiler/implementation/lib/js_helper.dart b/lib/compiler/implementation/lib/js_helper.dart
index 3348cf2f646f30a12ca32b32b10b431c291f5c66..1dda4ae6e5c940dd647123ad0806eeb3e75d976b 100644
--- a/lib/compiler/implementation/lib/js_helper.dart
+++ b/lib/compiler/implementation/lib/js_helper.dart
@@ -755,6 +755,10 @@ makeLiteralListConst(list) {
   return list;
 }
 
+throwRuntimeError(message) {
+  throw new RuntimeError(message);
+}
+
 /**
  * Called from catch blocks in generated code to extract the Dart
  * exception from the thrown value. The thrown value may have been