<rdar://problem/10760649>

Fixed another double file descriptor close issue that could occur when destroying a ProcessGDBRemote() object. There was a race which was detected by our fd_interposing library:

error: /Applications/Xcode.app/Contents/MacOS/Xcode (pid=55222): close (fd=60) resulted in EBADF:
0   libFDInterposing.dylib              0x00000001082be8ca close$__interposed__ + 666
1   LLDB                                0x00000001194fde91 lldb_private::ConnectionFileDescriptor::Close(int&, lldb_private::Error*) + 97
2   LLDB                                0x00000001194fddcd lldb_private::ConnectionFileDescriptor::Disconnect(lldb_private::Error*) + 143
3   LLDB                                0x00000001194fe249 lldb_private::ConnectionFileDescriptor::Read(void*, unsigned long, unsigned int, lldb::ConnectionStatus&, lldb_private::Error*) + 835
4   LLDB                                0x00000001194fc320 lldb_private::Communication::Read(void*, unsigned long, unsigned int, lldb::ConnectionStatus&, lldb_private::Error*) + 634
5   LLDB                                0x000000011959c7f4 GDBRemoteCommunication::WaitForPacketWithTimeoutMicroSecondsNoLock(StringExtractorGDBRemote&, unsigned int) + 228
6   LLDB                                0x000000011959c6b5 GDBRemoteCommunication::WaitForPacketWithTimeoutMicroSeconds(StringExtractorGDBRemote&, unsigned int) + 49
7   LLDB                                0x0000000119629a71 GDBRemoteCommunicationClient::SendContinuePacketAndWaitForResponse(ProcessGDBRemote*, char const*, unsigned long, StringExtractorGDBRemote&) + 509
8   LLDB                                0x00000001195a4076 ProcessGDBRemote::AsyncThread(void*) + 514
9   LLDB                                0x0000000119568094 ThreadCreateTrampoline(void*) + 91
10  libsystem_c.dylib                   0x00007fff8ca028bf _pthread_start + 335
11  libsystem_c.dylib                   0x00007fff8ca05b75 thread_start + 13

fd=60 was previously closed with this event:
pid=55222: close (fd=60) => 0
0   libFDInterposing.dylib              0x00000001082be870 close$__interposed__ + 576
1   LLDB                                0x00000001194fde91 lldb_private::ConnectionFileDescriptor::Close(int&, lldb_private::Error*) + 97
2   LLDB                                0x00000001194fddcd lldb_private::ConnectionFileDescriptor::Disconnect(lldb_private::Error*) + 143
3   LLDB                                0x00000001194fbf00 lldb_private::Communication::Disconnect(lldb_private::Error*) + 92
4   LLDB                                0x00000001195a2a77 ProcessGDBRemote::StopAsyncThread() + 89
5   LLDB                                0x00000001195a2bf6 ProcessGDBRemote::DoDestroy() + 310
6   LLDB                                0x00000001195f938d lldb_private::Process::Destroy() + 85
7   LLDB                                0x0000000118819b48 lldb::SBProcess::Kill() + 72
8   DebuggerLLDB                        0x0000000117264358 DBGLLDBSessionThread(void*) + 4450
9   LLDB                                0x0000000119568094 ThreadCreateTrampoline(void*) + 91
10  libsystem_c.dylib                   0x00007fff8ca028bf _pthread_start + 335
11  libsystem_c.dylib                   0x00007fff8ca05b75 thread_start + 13

fd=60 was created with this event:
pid=55222: socket (domain = 2, type = 1, protocol = 6) => fd=60
0   libFDInterposing.dylib              0x00000001082bc968 socket$__interposed__ + 600
1   LLDB                                0x00000001194fd75f lldb_private::ConnectionFileDescriptor::ConnectTCP(char const*, lldb_private::Error*) + 179
.....

llvm-svn: 149103