Emit declarations for typedefs that are needed by reflection.

tests/lib/lib.status

Index: tests/lib/lib.status
diff --git a/tests/lib/lib.status b/tests/lib/lib.status
index e16c839349884094ae50399c0c0da7c81a9c3fa8..4f510388804558375fdfaaf7e27d1f95b7960f7f 100644
--- a/tests/lib/lib.status
+++ b/tests/lib/lib.status
@@ -204,7 +204,6 @@ async/schedule_microtask6_test: Fail             # Issue 10957 - may be related
 convert/json_lib_test: Fail # Issue 10961
 
 [ $compiler == dart2js && $minified ]
-mirrors/typedef_test/01: Fail # http://dartbug.com/6490
 mirrors/mirrors_used_get_name_test: RuntimeError
 mirrors/mirrors_used_get_name2_test: RuntimeError
 
@@ -253,6 +252,8 @@ mirrors/mirrors_used_inheritance_test: RuntimeError # Issue 16048
 
 async/timer_not_available_test: SkipByDesign # only meant to test when there is no way to implement timer (currently only in d8)
 
+mirrors/typedef_declaration_test/01: Fail # dartbug.com/16048. Remove multitest marker when it passes.
+
 [ $compiler == none && ( $runtime == drt || $runtime == dartium || $runtime == ContentShellOnAndroid) ]
 async/schedule_microtask6_test: Fail # Issue 10910
 async/timer_test: Fail, Pass # Issue 15487