Report an error from dart2dart when deferred loading is used.

tests/language/language_dart2js.status

 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 [ $compiler == dart2js || $compiler == dart2dart ]
 override_inheritance_mixed_test/08: Fail # Issue 18124
 override_inheritance_mixed_test/09: Fail # Issue 18124
 bad_constructor_test/05: CompileTimeError # Issue 13669
 full_stacktrace1_test: Pass, RuntimeError # Issue 12698
 full_stacktrace2_test: Pass, RuntimeError # Issue 12698
@@ skipping 222 matching lines @@
 # DartVM problem.
 constructor5_test: Fail
 constructor6_test: Fail
 closure_in_initializer_test: Fail
 
 # Minified mode failures.
 
 new_expression_type_args_test/00: Fail # Wrongly reports compile-time error.
 new_expression_type_args_test/01: Fail # Wrongly reports compile-time error.
 
+deferred*: skip # Issue 17523
+
 [ $compiler == dart2dart && $minified ]
 cyclic_type_test/0*: Fail # Issue 12605.
 cyclic_type2_test: Fail # Issue 12605.
 super_getter_setter_test: Fail # Issue 11065.
 f_bounded_quantification4_test: Fail # Issue 12605.
 f_bounded_quantification5_test: Fail # Issue 12605.
 type_variable_typedef_test: Fail # Issue 11467
 type_variable_conflict2_test/01: RuntimeError # Issue 16180
 
 invocation_mirror_test: Fail, OK # Issue 12706 (hardcoded names).
@@ skipping 14 matching lines @@
 
 [ ($compiler == dart2js && $csp)]
 deferred_constraints_type_annotation_test/*: Skip # Issue 16898
 deferred_constraints_constants_test/*: Skip # Issue 16898
 deferred_no_such_method_test*: Skip # Issue 16898
 deferred_constraints_type_annotation_old_syntax_test/*: Skip # Issue 16898
 deferred_constraints_constants_old_syntax_test/*: Skip # Issue 16898
 
 [ $compiler == dart2js && $runtime == d8 && $system == windows ]
 *deferred*: Skip # Issue 17458