Clarify canonicalization test expectations

Agent-Logs-Url: https://github.com/dadhi/FastExpressionCompiler/sessions/5ca8e295-4a63-4eb7-92fb-705afa82cdf4

Co-authored-by: dadhi <39516+dadhi@users.noreply.github.com>

Author: Copilot

test/FastExpressionCompiler.LightExpression.UnitTests/LightExpressionTests.cs

@@ -518,7 +518,9 @@ public void Can_canonicalize_directly_built_flat_expression()
                     expectedParameter)
                 .ToFlatExpression();
 
-            Asserts.IsTrue(fe.Nodes.Count > canonical.Nodes.Count);
+            // Direct construction keeps one unreachable constant plus four cloned linkable leaves
+            // (parameter, variable, label target, and nested-lambda capture) that disappear after canonical rebuild.
+            Asserts.AreEqual(expected.Nodes.Count + 5, fe.Nodes.Count);
             AssertFlatShapeIgnoringParameterNamesAndConstantValues(expected, canonical);
             Asserts.AreEqual(6, ((System.Linq.Expressions.Expression<Func<int, int>>)canonical.ToExpression()).Compile()(5));
         }