Add test directive to include other files used by a test in its compiled output directory.

tests/standalone/io/secure_socket_test.dart

Index: tests/standalone/io/secure_socket_test.dart
diff --git a/tests/standalone/io/secure_socket_test.dart b/tests/standalone/io/secure_socket_test.dart
index bf128df0604d9c0373c5f0c5e8e3041ec30810f1..9a9275708e790356dc866491a91468203991ac24 100644
--- a/tests/standalone/io/secure_socket_test.dart
+++ b/tests/standalone/io/secure_socket_test.dart
@@ -6,6 +6,12 @@
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
+// OtherResources=certificates/server_chain.pem
+// OtherResources=certificates/server_key.pem
+// OtherResources=certificates/trusted_certs.pem
+// OtherResources=certificates/server_chain.p12
+// OtherResources=certificates/server_key.p12
+// OtherResources=certificates/trusted_certs.p12
 
 import "package:async_helper/async_helper.dart";
 import "package:expect/expect.dart";