Add proper API for creating private symbols wrt a library.

tests/lib/lib.status

Index: tests/lib/lib.status
diff --git a/tests/lib/lib.status b/tests/lib/lib.status
index 911bad490fe275a0e1b097003562f6311553212a..26b65c871bb99fb622b01e897949e2f8b31a8009 100644
--- a/tests/lib/lib.status
+++ b/tests/lib/lib.status
@@ -6,9 +6,16 @@
 mirrors/delegate_test: RuntimeError # Issue 13864
 
 [ $compiler == dart2js ]
+async/run_async3_test: RuntimeError # _enqueueImmediate runs after Timer. http://dartbug.com/9002
+async/run_async4_test: Pass, RuntimeError # no global exception handler in isolates. http://dartbug.com/9012
+async/run_async6_test: RuntimeError # global error handling is not supported. http://dartbug.com/5958
+async/stream_controller_async_test: Pass, Fail # Issue 13608
+
 math/double_pow_test: RuntimeError
 math/low_test: RuntimeError
 math/random_test: RuntimeError
+
+mirrors/closures_test/none: RuntimeError # Issue 6490
 mirrors/closure_mirror_find_in_context_test: Fail # Issue 6490
 mirrors/constructor_kinds_test: RuntimeError # Issue 13799
 mirrors/equality_test/02: RuntimeError # Issue 12333
@@ -25,11 +32,13 @@ mirrors/generic_mixin_applications_test: RuntimeError # Issue 12333
 mirrors/generics_substitution_test: RuntimeError # Issue 12087
 mirrors/hierarchy_invariants_test: RuntimeError # Issue 11863
 mirrors/initializing_formals_test: CompileTimeError # Issue 12164
+mirrors/intercepted_superclass_test: RuntimeError # Issue 13644
 mirrors/invoke_test: RuntimeError # Issue 11954
 mirrors/invoke_closurization_test: RuntimeError # Issue 13002
 mirrors/invoke_named_test/none: RuntimeError # Issue 12863
 mirrors/invoke_private_test: CompileTimeError # Issue 12164
 mirrors/invoke_throws_test: RuntimeError # Issue 11954
+mirrors/library_metadata2_test/01: CompileTimeError # Issue 13633
 mirrors/library_uri_io_test: Skip # Not intended for dart2js as it uses dart:io.
 mirrors/method_mirror_name_test: RuntimeError # Issue 6335
 mirrors/method_mirror_properties_test: RuntimeError # Issue 11861
@@ -41,21 +50,17 @@ mirrors/new_instance_with_type_arguments_test: RuntimeError # Issue 12333
 mirrors/null_test : RuntimeError # Issue 12129
 mirrors/parameter_test/none: RuntimeError # Issue 6490
 mirrors/parameter_metadata_test: CompileTimeError # Issue 10905
+mirrors/private_symbol_test: CompileTimeError # Issue 13597
 mirrors/proxy_type_test: RuntimeError # Issue 13842
+mirrors/redirecting_factory_test/none: RuntimeError # Issue 6490
+mirrors/redirecting_factory_test/02: RuntimeError # Issue 6490
 mirrors/reflected_type_test: RuntimeError # Issue 12607
+mirrors/symbol_validation_test: RuntimeError # Issue 13597
 mirrors/type_argument_is_type_variable_test: RuntimeError # Issue 12333
+mirrors/typedef_test/none: RuntimeError # http://dartbug.com/6490
 mirrors/typedef_metadata_test: RuntimeError # Issue 12785
 mirrors/typevariable_mirror_metadata_test: CompileTimeError # Issue 10905
 mirrors/unnamed_library_test: RuntimeError # Issue 10580
-async/run_async3_test: RuntimeError # _enqueueImmediate runs after Timer. http://dartbug.com/9002
-async/run_async4_test: Pass, RuntimeError # no global exception handler in isolates. http://dartbug.com/9012
-async/run_async6_test: RuntimeError # global error handling is not supported. http://dartbug.com/5958
-mirrors/typedef_test/none: RuntimeError # http://dartbug.com/6490
-mirrors/redirecting_factory_test/none: RuntimeError # Issue 6490
-mirrors/redirecting_factory_test/02: RuntimeError # Issue 6490
-mirrors/closures_test/none: RuntimeError # Issue 6490
-mirrors/library_metadata2_test/01: CompileTimeError # Issue 13633
-async/stream_controller_async_test: Pass, Fail # Issue 13608
 
 [ $compiler == dart2js && $unchecked ]
 mirrors/generic_bounded_test/02: RuntimeError # Issue 12087
@@ -160,11 +165,13 @@ mirrors/native_class_test: Fail, OK # This test is meant to run in a browser.
 async/run_async3_test: Fail # _enqueueImmediate runs after Timer. http://dartbug.com/9001.
 mirrors/hierarchy_test: Fail # TODO(ahe): This test is slightly broken. http://dartbug.com/12464
 mirrors/mixin_test/01: Fail, OK # TODO(ahe): Slight broken test to ensure test coverage on dart2js.
+mirrors/intercepted_object_test: Fail, OK # TODO(ahe): Slight broken test to ensure test coverage on dart2js.
 mirrors/typedef_test/01: Fail, OK # Incorrect dart2js behavior.
 mirrors/closures_test/01: Fail, OK # Incorrect dart2js behavior.
 
 mirrors/generic_function_typedef_test: RuntimeError # Issue 12282
 mirrors/generic_f_bounded_test: RuntimeError # Issue 14000
+mirrors/symbol_validation_test: RuntimeError # Issue 13596
 
 async/timer_isolate_test: Skip # See Issue 4997
 async/timer_not_available_test: SkipByDesign # only meant to test when there is no way to implement timer (currently only in d8)