Fixed remote failures in TestCPP11EnumTypes, probably others

[vharron]

Summary

Typically, LLGS only sends stdout/stderr notifications when the inferior
process is running.

Because LLGS reads stdout from the process in a separate thread, sometimes
these stdout notifications can be received after the server has sent a thread
stop message. The host isn't expecting stdout to be generated by the target
after a stop message and these messages interfere with the host's request/
response paradigm.

[clayborg]

Looks good.

[tberghammer]

LGTM

[labath]

lgtm, nice catch

lldb/trunk/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp

GDBRemoteCommunicationServerLLGS::ProcessStateChanged (NativeProcessProtocol *process, lldb::StateType state)
     if (log)
     {
         log->Printf ("GDBRemoteCommunicationServerLLGS::%s called with NativeProcessProtocol pid %" PRIu64 ", state: %s",
                 __FUNCTION__,
                 process->GetID (),
                 StateAsCString (state));
     }
 
+    // Make sure we get all of the pending stdout/stderr from the inferior
+    // and send it to the lldb host before we send the state change
+    // notification
+    m_stdio_communication.SynchronizeWithReadThread();
+
     switch (state)
     {
     case StateType::eStateExited:
         HandleInferiorState_Exited (process);
         break;
 
     case StateType::eStateStopped:
         HandleInferiorState_Stopped (process);