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.

hipamd/src/hip_runtime.cpp

@@ -51,18 +51,11 @@ extern "C" BOOL WINAPI DllMain(HINSTANCE hinst, DWORD reason, LPVOID reserved) {
 #endif  // DEBUG
       hip::PlatformState::instance().setDynamicLibraryHandle(static_cast<void*>(hinst));
       break;
-    case DLL_PROCESS_DETACH: {
-      amd::Thread* thread = amd::Thread::current();
-      if (!(thread != nullptr ||
-            ((thread = new amd::HostThread()) != nullptr && thread == amd::Thread::current()))) {
-        return true;
-      }
+    case DLL_PROCESS_DETACH:
       hip::ihipDestroyDevice();
-    } break;
-    case DLL_THREAD_DETACH: {
-      amd::Thread* thread = amd::Thread::current();
-      delete thread;
-    } break;
+      break;
+    case DLL_THREAD_DETACH:
+      break;
     default:
       break;
   }