[fix](Nereids): fix bugs in struct info (apache#27890)

fe/fe-core/src/main/java/org/apache/doris/nereids/jobs/joinorder/hypergraph/HyperGraph.java

@@ -431,14 +431,13 @@ private void addStructInfo(HyperGraph other) {
     private Pair<BitSet, Long> buildStructInfo(Plan plan) {
         if (plan instanceof GroupPlan) {
             Group group = ((GroupPlan) plan).getGroup();
-            buildStructInfo(group.getLogicalExpressions().get(0).getPlan());
             List<HyperGraph> childGraphs = ((GroupPlan) plan).getGroup().getHyperGraphs();
             if (childGraphs.size() != 0) {
                 int idx = addStructInfoNode(childGraphs);
                 return Pair.of(new BitSet(), LongBitmap.newBitmap(idx));
             }
             GroupExpression groupExpression = group.getLogicalExpressions().get(0);
-            buildStructInfo(groupExpression.getPlan()
+            return buildStructInfo(groupExpression.getPlan()
                     .withChildren(
                             groupExpression.children().stream().map(GroupPlan::new).collect(Collectors.toList())));
         }

fe/fe-core/src/test/java/org/apache/doris/nereids/rules/exploration/mv/BuildStructInfoTest.java

@@ -0,0 +1,45 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package org.apache.doris.nereids.rules.exploration.mv;
+
+import org.apache.doris.nereids.jobs.joinorder.hypergraph.HyperGraph;
+import org.apache.doris.nereids.sqltest.SqlTestBase;
+import org.apache.doris.nereids.util.PlanChecker;
+
+import org.junit.jupiter.api.Test;
+
+class BuildStructInfoTest extends SqlTestBase {
+    @Test
+    void testSimpleSQL() {
+        String sql = "select * from T1, T2, T3, T4 "
+                + "where "
+                + "T1.id = T2.id and "
+                + "T2.score = T3.score and "
+                + "T3.id = T4.id";
+        PlanChecker.from(connectContext)
+                .analyze(sql)
+                .rewrite()
+                .deriveStats()
+                .matches(logicalJoin()
+                        .when(j -> {
+                            HyperGraph.toStructInfo(j);
+                            return true;
+                        }));
+
+    }
+}