Support deferred library prefix syntax

tests/language/language.status

Index: tests/language/language.status
===================================================================
--- tests/language/language.status	(revision 34312)
+++ tests/language/language.status	(working copy)
@@ -21,16 +21,17 @@
 mixin_forwarding_constructor2_test: Fail # Issue 13641
 
 # Issue 17521
-deferred_constraints_constants_test/*: Fail, Pass
-deferred_constraints_type_annotation_test/*: Fail, Pass
-deferred_shadow_load_library_test: Fail
-deferred_closurize_load_library_test: Fail
-deferred_constraints_type_annotation_old_syntax_test/as_operation: Fail
-deferred_constraints_type_annotation_old_syntax_test/is_check: Fail
-deferred_constraints_type_annotation_old_syntax_test/catch_check: Fail
-deferred_constraints_type_annotation_old_syntax_test/new_before_load: Fail
+deferred_constraints_constants_test/default_argument2: Fail
+deferred_constraints_constants_test/metadata1: Fail
+deferred_constraints_constants_test/metadata3: Fail
+deferred_constraints_constants_test/metadata2: Fail
 
+
 # These test use the old syntax, and will be phased out.
+deferred_constraints_type_annotation_old_syntax_test/as_operation: Fail, Ok
+deferred_constraints_type_annotation_old_syntax_test/is_check: Fail, Ok
+deferred_constraints_type_annotation_old_syntax_test/catch_check: Fail, Ok
+deferred_constraints_type_annotation_old_syntax_test/new_before_load: Fail, Ok
 deferred_constraints_constants_old_syntax_test/reference1: Fail, Ok
 deferred_constraints_constants_old_syntax_test/reference2: Fail, Ok
 deferred_constraints_constants_old_syntax_test/metadata1: Fail, Ok
@@ -41,18 +42,15 @@
 deferred_constraints_constants_old_syntax_test/constructor1: Fail, Ok
 deferred_constraints_constants_old_syntax_test/constructor2: Fail, Ok
 
-[ ($compiler == none || $compiler == dart2dart)]
-# Issue 17521, 17523
+cyclic_type_test: Fail, OK # Issue 17629
+
+[ ($compiler == dart2dart)]
+# Issue 17523
 deferred_constraints_type_annotation_test/as_operation: Fail
 deferred_constraints_type_annotation_test/is_check: Fail
 deferred_constraints_type_annotation_test/catch_check: Fail
 deferred_constraints_type_annotation_test/new_before_load: Fail
 deferred_load_library_wrong_args_test/none: Fail
-
-cyclic_type_test: Fail, OK # Issue 17629
-
-[ ($compiler == dart2dart)]
-# Issue 17523
 deferred_constraints_type_annotation_test/*: Fail, Pass
 deferred_constraints_constants_test/*: Fail, Pass
 deferred_constraints_type_annotation_old_syntax_test/as_operation: Fail