Move shared class to it's own library.

tests/language/deferred_type_dependency_test.dart

Index: tests/language/deferred_type_dependency_test.dart
diff --git a/tests/language/deferred_type_dependency_test.dart b/tests/language/deferred_type_dependency_test.dart
index c8efcd54a623028999a9f6331335b70730e7e9ce..766834e81b5d916e3c12d7ec426a96473da22c07 100644
--- a/tests/language/deferred_type_dependency_test.dart
+++ b/tests/language/deferred_type_dependency_test.dart
@@ -9,10 +9,6 @@ import "deferred_type_dependency_lib1.dart" deferred as lib1;
 import "deferred_type_dependency_lib2.dart" deferred as lib2;
 import "package:expect/expect.dart";
 
-class A {
-  var p = true;
-}
-
 main() async {
   await lib1.loadLibrary();
   // Split the cases into a multi-test to test each feature separately.