Implemented dbsim high prio service log_dummy_write_set()

The empty implementation of log_dummy_write_set() in dbsim
high priority service implementation left unreleased commit
order critical section behind whenever remote write set failed
certification. Added calls to do empty commit to release the
critical section.

Other:

Implemented ostream operator<< for wsrep:🧵:id, and added
printout of owning thread into transaction debug output.

src/CMakeLists.txt

@@ -13,6 +13,7 @@ add_library(wsrep-lib
   seqno.cpp
   view.cpp
   server_state.cpp
+  thread.cpp
   transaction.cpp
   wsrep_provider_v26.cpp)
 target_link_libraries(wsrep-lib wsrep_api_v26 pthread dl)

src/thread.cpp

@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2019 Codership Oy <info@codership.com>
+ *
+ * This file is part of wsrep-lib.
+ *
+ * Wsrep-lib is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Wsrep-lib is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with wsrep-lib.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "wsrep/thread.hpp"
+
+#include <ostream>
+
+std::ostream& wsrep::operator<<(std::ostream& os, const wsrep::thread::id& id)
+{
+    std::ios_base::fmtflags orig_flags(os.flags());
+    os << std::hex << id.thread_;
+    os.flags(orig_flags);
+    return os;
+}

src/transaction.cpp

@@ -758,8 +758,6 @@ int wsrep::transaction::after_statement()
             ret = provider().commit_order_enter(ws_handle_, ws_meta_);
             if (ret == 0)
             {
-                // client_state_.server_state().last_committed_gtid(
-                //   ws_meta.gtid());
                 provider().commit_order_leave(ws_handle_, ws_meta_);
             }
         }
@@ -1550,6 +1548,7 @@ void wsrep::transaction::debug_log_state(
         << ", bytes: " << streaming_context_.bytes_certified()
         << ", sr_rb: " << streaming_context_.rolled_back()
         << "\n    own: " << (client_state_.owning_thread_id_ == wsrep::this_thread::get_id())
+        << " thread_id: " << client_state_.owning_thread_id_
         << "");
 }