Remove unnecessary locks on DiscoveryNodeManager

Threads which try to 'getAllNode' or 'getActiveConnectorNodes'
could be against with thread that are refreshing workers state.
This control of race condition seems unnecessary, so removing locks
may be improve performance slightly.

core/trino-main/src/main/java/io/trino/metadata/DiscoveryNodeManager.java

@@ -82,14 +82,11 @@ public final class DiscoveryNodeManager
     private final InternalNode currentNode;
     private final boolean allCatalogsOnAllNodes;
 
-    @GuardedBy("this")
     private Optional<SetMultimap<CatalogHandle, InternalNode>> activeNodesByCatalogHandle = Optional.empty();
 
-    @GuardedBy("this")
-    private AllNodes allNodes;
+    private volatile AllNodes allNodes;
 
-    @GuardedBy("this")
-    private Set<InternalNode> coordinators;
+    private volatile Set<InternalNode> coordinators;
 
     @GuardedBy("this")
     private final List<Consumer<AllNodes>> listeners = new ArrayList<>();
@@ -305,7 +302,7 @@ private boolean isNodeShuttingDown(String nodeId)
     }
 
     @Override
-    public synchronized AllNodes getAllNodes()
+    public AllNodes getAllNodes()
     {
         return allNodes;
     }
@@ -343,7 +340,7 @@ public Set<InternalNode> getNodes(NodeState state)
     }
 
     @Override
-    public synchronized Set<InternalNode> getActiveCatalogNodes(CatalogHandle catalogHandle)
+    public Set<InternalNode> getActiveCatalogNodes(CatalogHandle catalogHandle)
     {
         // activeNodesByCatalogName is immutable
         return activeNodesByCatalogHandle
@@ -352,7 +349,7 @@ public synchronized Set<InternalNode> getActiveCatalogNodes(CatalogHandle catalo
     }
 
     @Override
-    public synchronized NodesSnapshot getActiveNodesSnapshot()
+    public NodesSnapshot getActiveNodesSnapshot()
     {
         return new NodesSnapshot(allNodes.getActiveNodes(), activeNodesByCatalogHandle);
     }
@@ -364,7 +361,7 @@ public InternalNode getCurrentNode()
     }
 
     @Override
-    public synchronized Set<InternalNode> getCoordinators()
+    public Set<InternalNode> getCoordinators()
     {
         return coordinators;
     }