Fix host-checked + checked by registering when a class is being instantiated, not when being proces…

lib/compiler/implementation/compiler.dart

Index: lib/compiler/implementation/compiler.dart
===================================================================
--- lib/compiler/implementation/compiler.dart	(revision 11874)
+++ lib/compiler/implementation/compiler.dart	(working copy)
@@ -721,11 +721,6 @@
     backend.codegen(work);
   }
 
-  void registerInstantiatedClass(ClassElement cls) {
-    enqueuer.resolution.registerInstantiatedClass(cls);
-    enqueuer.codegen.registerInstantiatedClass(cls);
-  }
-
   DartType resolveTypeAnnotation(Element element, TypeAnnotation annotation) {
     return resolver.resolveTypeAnnotation(element, annotation);
   }