Adjust OutputBuffer is full condition

Assume OutputBuffer is full when the limit is reached but not yet exceeded.

This change does not impact real scenarious much, but quite convinient
when testing

velox/exec/OutputBuffer.cpp

@@ -474,7 +474,7 @@ bool OutputBuffer::enqueue(
         VELOX_UNREACHABLE(PartitionedOutputNode::kindString(kind_));
     }
 
-    if (bufferedBytes_ > maxSize_ && future) {
+    if (bufferedBytes_ >= maxSize_ && future) {
       promises_.emplace_back("OutputBuffer::enqueue");
       *future = promises_.back().getSemiFuture();
       blocked = true;