Remove unnecessary lock in TerminalLogger.UpdateNodeStatus

src/MSBuild/TerminalLogger/TerminalLogger.cs

@@ -91,6 +91,10 @@ public ProjectContext(BuildEventContext context)
     /// <summary>
     /// Tracks the work currently being done by build nodes. Null means the node is not doing any work worth reporting.
     /// </summary>
+    /// <remarks>
+    /// There is no locking around access to this data structure despite it being accessed concurrently by multiple threads.
+    /// However, reads and writes to locations in an array is atomic, so locking is not required.
+    /// </remarks>
     private NodeStatus?[] _nodes = Array.Empty<NodeStatus>();
 
     /// <summary>
@@ -701,11 +705,8 @@ private void TargetStarted(object sender, TargetStartedEventArgs e)
 
     private void UpdateNodeStatus(BuildEventContext buildEventContext, NodeStatus? nodeStatus)
     {
-        lock (_lock)
-        {
-            int nodeIndex = NodeIndexForContext(buildEventContext);
-            _nodes[nodeIndex] = nodeStatus;
-        }
+        int nodeIndex = NodeIndexForContext(buildEventContext);
+        _nodes[nodeIndex] = nodeStatus;
     }
 
     /// <summary>