SWDEV-520352 - Remove HostThread and legacy monitor (#230)

* SWDEV-520352 - Remove HostThread and legacy monitor

Remove HostThread, semaphore and  legacy monitor.
Make original logics of thread and command queue stricker.
Add more comments to make logics clearer.
Some other minor improvement.

Also part of SWDEV-458943.

rocclr/device/rocm/rocvirtual.cpp

@@ -186,12 +186,6 @@ void Timestamp::checkGpuTime() {
 bool HsaAmdSignalHandler(hsa_signal_value_t value, void* arg) {
   Timestamp* ts = reinterpret_cast<Timestamp*>(arg);
 
-  amd::Thread* thread = amd::Thread::current();
-  if (!(thread != nullptr ||
-      ((thread = new amd::HostThread()) != nullptr && thread == amd::Thread::current()))) {
-    return false;
-  }
-
   if (amd::activity_prof::IsEnabled(OP_ID_DISPATCH)) {
     amd::Command* head = ts->getParsedCommand();
     if (head == nullptr) {