Fix memory leak in ServiceTestMessageHandler.

runtime/vm/service_test.cc

Index: runtime/vm/service_test.cc
diff --git a/runtime/vm/service_test.cc b/runtime/vm/service_test.cc
index 0bbed746f6b22d6367c3cbcbc4050674db2287d5..d0d488ab6f6090b49d64c6c16b818cbf8eff3570 100644
--- a/runtime/vm/service_test.cc
+++ b/runtime/vm/service_test.cc
@@ -33,6 +33,7 @@ class ServiceTestMessageHandler : public MessageHandler {
   MessageStatus HandleMessage(Message* message) {
     if (_msg != NULL) {
       free(_msg);
+      _msg = NULL;
     }
 
     // Parse the message.
@@ -58,6 +59,8 @@ class ServiceTestMessageHandler : public MessageHandler {
       _msg = strdup(reinterpret_cast<char*>(response.DataAddr(0)));
     }
 
+    delete message;
+
     return kOK;
   }