compiler: Add thread rendezvous predicate

Author: Codex

devito/ir/clusters/cluster.py

@@ -248,6 +248,14 @@ def is_phase_marker(self):
     def is_critical_region(self):
         return self._is_type(CriticalRegion)
 
+    @cached_property
+    def is_thread_rendezvous(self):
+        """
+        True if it contains a synchronization point at which all participating
+        threads must arrive before any may proceed.
+        """
+        return self.is_thread_pool_sync and not self.is_thread_wait
+
     @cached_property
     def is_thread_pool_sync(self):
         return self._is_type(ThreadPoolSync)