dart2js: Support isDeferred on DependencyMirrors.

pkg/pkg.status

Index: pkg/pkg.status
diff --git a/pkg/pkg.status b/pkg/pkg.status
index d4554fe22b91dbe23a1bbe85a43f9989c1df3351..acae7f1ce76b97525de6dc9679b10129f3d29d2b 100644
--- a/pkg/pkg.status
+++ b/pkg/pkg.status
@@ -186,17 +186,6 @@ analyzer2dart/test/driver_test: StaticWarning # Issue 22418
 analyzer2dart/test/sexpr_test: StaticWarning # Issue 22418
 analyzer2dart/test/tree_shaker_test: StaticWarning # Issue 22418
 analyzer2dart/test/end2end_test: StaticWarning # Issue 22418
-docgen/test/multi_library_test: StaticWarning # Issue 22475
-docgen/test/method_param_test: StaticWarning # Issue 22475
-docgen/test/async_await_test: StaticWarning # Issue 22475
-docgen/test/typedef_test: StaticWarning # Issue 22475
-docgen/test/metadata_test: StaticWarning # Issue 22475
-docgen/test/native_extensions_test: StaticWarning # Issue 22475
-docgen/test/generate_json_test: StaticWarning # Issue 22475
-docgen/test/only_lib_content_in_pkg_test: StaticWarning # Issue 22475
-docgen/test/constant_argument_test: StaticWarning # Issue 22475
-docgen/test/inherited_comments_test: StaticWarning # Issue 22475
-docgen/test/single_library_test: StaticWarning # Issue 22475
 
 [ $runtime == safari || $runtime == safarimobilesim || $runtime == chrome || $runtime == ff || $ie ]
 # Various issues due to limited browser testing in Angular.