[JSON] Use LLVM's library for encoding JSON in GDBRemoteCommunicationServerPlatform

[JDevlieghere]

Summary

This patch replaces the LLDB's JSON implementation with the one from
LLVM in GDBRemoteCommunicationServerPlatform.

[labath]

LG, with the same caveat about about namespaces.

lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerPlatform.cpp

 #include <chrono>
 #include <csignal>
 #include <cstring>
 #include <mutex>
 #include <sstream>
 #include <thread>
 
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/JSON.h"
 #include "llvm/Support/Threading.h"
 
 #include "lldb/Host/Config.h"
 #include "lldb/Host/ConnectionFileDescriptor.h"
 #include "lldb/Host/FileAction.h"
 #include "lldb/Host/Host.h"
 #include "lldb/Host/HostInfo.h"
 #include "lldb/Target/Platform.h"
 #include "lldb/Target/UnixSignals.h"
 #include "lldb/Utility/GDBRemote.h"
-#include "lldb/Utility/JSON.h"
 #include "lldb/Utility/Log.h"
 #include "lldb/Utility/StreamString.h"
 #include "lldb/Utility/StructuredData.h"
 #include "lldb/Utility/UriParser.h"
 
 #include "lldb/Utility/StringExtractorGDBRemote.h"
 
 using namespace lldb;
-using namespace lldb_private;
 using namespace lldb_private::process_gdb_remote;
+using namespace lldb_private;
+using namespace llvm;
 
 // GDBRemoteCommunicationServerPlatform constructor
 GDBRemoteCommunicationServerPlatform::GDBRemoteCommunicationServerPlatform(
     const Socket::SocketProtocol socket_protocol, const char *socket_scheme)
     : GDBRemoteCommunicationServerCommon("gdb-remote.server",
                                          "gdb-remote.server.rx_packet"),
       m_socket_protocol(socket_protocol), m_socket_scheme(socket_scheme),
       m_spawned_pids_mutex(), m_port_map(), m_port_offset(0) {

 }
 
 GDBRemoteCommunication::PacketResult
 GDBRemoteCommunicationServerPlatform::Handle_qQueryGDBServer(
     StringExtractorGDBRemote &packet) {
   if (m_pending_gdb_server.pid == LLDB_INVALID_PROCESS_ID)
     return SendErrorResponse(4);
 
-  JSONObject::SP server_sp = std::make_shared<JSONObject>();
-  server_sp->SetObject("port",
-                       std::make_shared<JSONNumber>(m_pending_gdb_server.port));
+  json::Object server{{"port", m_pending_gdb_server.port}};
+
   if (!m_pending_gdb_server.socket_name.empty())
-    server_sp->SetObject(
-        "socket_name",
-        std::make_shared<JSONString>(m_pending_gdb_server.socket_name.c_str()));
+    server.try_emplace("socket_name", m_pending_gdb_server.socket_name);
 
-  JSONArray server_list;
-  server_list.AppendObject(server_sp);
+  json::Array server_list;
+  server_list.push_back(std::move(server));
 
   StreamGDBRemote response;
-  server_list.Write(response);
+  response.AsRawOstream() << std::move(server_list);
 
   StreamGDBRemote escaped_response;
   escaped_response.PutEscapedBytes(response.GetString().data(),
                                    response.GetSize());
   return SendPacketNoLock(escaped_response.GetString());
 }
 
 GDBRemoteCommunication::PacketResult