SWDEV-502365 - Track last used command

- This change tries to save extra synchronization packets we may insert
  as we didnt track the completion signals for every command. We track
the current enqueued command until it exits the enqueue stage. We also
record the exit scope to know if we flushed the caches
- Handle correct release scopes and store completion signal as HW events
- Use a new finishCommand implementation to only wait for the command
  passed as the argument

Change-Id: Ie4350c5dd24f5d48dfa6ccbabd892f0544caadcc

rocclr/platform/commandqueue.hpp

@@ -233,6 +233,9 @@ class HostQueue : public CommandQueue {
   //! Finish all queued commands
   void finish(bool cpu_wait = false);
 
+  //! Wait until finish of one command
+  void finishCommand(Command* command);
+
   //! Check if hostQueue empty snapshot
   bool isEmpty();