fix: restore IgnoreComet.scala in 3.5.8 Spark SQL test diff

The previous commit accidentally removed the IgnoreComet.scala file
creation from the diff, causing 94 compilation errors when applied
to Spark 3.5.8.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: andygrove

dev/diffs/3.5.8.diff

@@ -574,6 +574,57 @@ index 93275487f29..510e3087e0f 100644
            }.flatten
            assert(filters.contains(GreaterThan(scan.logicalPlan.output.head, Literal(5L))))
          }
+diff --git a/sql/core/src/test/scala/org/apache/spark/sql/IgnoreComet.scala b/sql/core/src/test/scala/org/apache/spark/sql/IgnoreComet.scala
+new file mode 100644
+index 00000000000..1ee842b6f62
+--- /dev/null
++++ b/sql/core/src/test/scala/org/apache/spark/sql/IgnoreComet.scala
+@@ -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.spark.sql
++
++import org.scalactic.source.Position
++import org.scalatest.Tag
++
++import org.apache.spark.sql.test.SQLTestUtils
++
++/**
++ * Tests with this tag will be ignored when Comet is enabled (e.g., via `ENABLE_COMET`).
++ */
++case class IgnoreComet(reason: String) extends Tag("DisableComet")
++case class IgnoreCometNativeIcebergCompat(reason: String) extends Tag("DisableComet")
++case class IgnoreCometNativeDataFusion(reason: String) extends Tag("DisableComet")
++case class IgnoreCometNativeScan(reason: String) extends Tag("DisableComet")
++
++/**
++ * Helper trait that disables Comet for all tests regardless of default config values.
++ */
++trait IgnoreCometSuite extends SQLTestUtils {
++  override protected def test(testName: String, testTags: Tag*)(testFun: => Any)(implicit
++      pos: Position): Unit = {
++    if (isCometEnabled) {
++      ignore(testName + " (disabled when Comet is on)", testTags: _*)(testFun)
++    } else {
++      super.test(testName, testTags: _*)(testFun)
++    }
++  }
++}
 diff --git a/sql/core/src/test/scala/org/apache/spark/sql/JoinHintSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/JoinHintSuite.scala
 index 7af826583bd..3c3def1eb67 100644
 --- a/sql/core/src/test/scala/org/apache/spark/sql/JoinHintSuite.scala