Issue 8365. Report error when user library imports an internal SDK library.

tests/language/language.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.
 
 # This directory contains tests that are intended to show the
 # current state of the language.
 
 # In order to maintain maximum test coverage for all builds,
 # please use the following procedure to mark a test
 # failed on architectures other than the one you are working on.
@@ skipping 659 matching lines @@
 getter_no_setter2_test/00: fail
 getter_no_setter2_test/03: fail
 getter_no_setter_test/00: fail
 getter_no_setter_test/01: fail
 getters_setters2_test/01: fail
 getters_setters_type_test/01: fail
 implicit_this_test/01: fail
 implicit_this_test/04: fail
 implicit_this_test/none: fail
 import_combinators_negative_test: fail
-import_private_test/01: fail
 infinite_switch_label_test: fail
 inst_field_initializer1_negative_test: fail
 instance_call_wrong_argument_count_negative_test: fail
 instance_method2_negative_test: fail
 instance_method_negative_test: fail
 instantiate_type_variable_negative_test: fail
 interface_cycle_negative_test: fail
 interface_inherit_field_test: fail
 interface_static_non_final_fields_negative_test: fail
 interface_test/00: fail
-internal_library_test/01: fail
 is_not_class2_negative_test: fail
 library_juxtaposition_test: fail
 licm_test: fail
 list_literal1_negative_test: fail
 list_literal_syntax_test/01: fail
 list_literal_syntax_test/02: fail
 list_literal_syntax_test/03: fail
 map_literal1_negative_test: fail
 map_literal3_test: fail
 method_override2_test/03: fail
@@ skipping 114 matching lines @@
 *: Skip
 
 [ $arch == simarm ]
 *: Skip
 
 [ $arch == mips ]
 *: Skip
 
 [ $arch == simmips ]
 *: Skip