Added a few tests, removed some error codes from Resolver

compiler/java/com/google/dart/compiler/resolver/CoreTypeProviderImplementation.java

Index: compiler/java/com/google/dart/compiler/resolver/CoreTypeProviderImplementation.java
diff --git a/compiler/java/com/google/dart/compiler/resolver/CoreTypeProviderImplementation.java b/compiler/java/com/google/dart/compiler/resolver/CoreTypeProviderImplementation.java
index 15f20b6ecb72ab88204289b171b6c8894fcf4c2f..5b95a0ac11ff05320762541558e73c2e1213f891 100644
--- a/compiler/java/com/google/dart/compiler/resolver/CoreTypeProviderImplementation.java
+++ b/compiler/java/com/google/dart/compiler/resolver/CoreTypeProviderImplementation.java
@@ -61,7 +61,7 @@ public class CoreTypeProviderImplementation implements CoreTypeProvider {
     if (element == null) {
       DartCompilationError error =
           new DartCompilationError(null, Location.NONE,
-              ResolverErrorCode.CANNOT_BE_RESOLVED, name);
+              ResolverErrorCode.CANNOT_RESOLVE_SDK_TYPE, name);
       listener.onError(error);
       return Types.newDynamicType();
     }
@@ -78,7 +78,7 @@ public class CoreTypeProviderImplementation implements CoreTypeProvider {
     if (element == null) {
       DartCompilationError error =
           new DartCompilationError(null, Location.NONE,
-              ResolverErrorCode.CANNOT_BE_RESOLVED, names[0]);
+              ResolverErrorCode.CANNOT_RESOLVE_SDK_TYPE, names[0]);
       listener.onError(error);
       return Types.newDynamicType();
     }
@@ -174,7 +174,7 @@ public class CoreTypeProviderImplementation implements CoreTypeProvider {
 
   @Override
   public InterfaceType getIteratorType(Type elementType) {
-    return iteratorType.subst(Arrays.asList(elementType), 
+    return iteratorType.subst(Arrays.asList(elementType),
         iteratorType.getElement().getTypeParameters());
   }
 }