[SPARK-30719][SQL] Add unit test to verify the log warning print when intentionally skip AQE

### What changes were proposed in this pull request?

This is a follow up in [#27452](#27452).
Add a unit test to verify whether the log warning is print when intentionally skip AQE.

### Why are the changes needed?

Add unit test

### Does this PR introduce any user-facing change?

No

### How was this patch tested?

adding unit test

Closes #27515 from JkSelf/aqeLoggingWarningTest.

Authored-by: jiake <ke.a.jia@intel.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>

Author: JkSelf

sql/core/src/test/scala/org/apache/spark/sql/execution/adaptive/AdaptiveQueryExecSuite.scala

@@ -789,4 +789,19 @@ class AdaptiveQueryExecSuite
       assert(plan.isInstanceOf[AdaptiveSparkPlanExec])
     }
   }
+
+  test("SPARK-30719: do not log warning if intentionally skip AQE") {
+    val testAppender = new LogAppender("aqe logging warning test when skip")
+    withLogAppender(testAppender) {
+      withSQLConf(
+        SQLConf.ADAPTIVE_EXECUTION_ENABLED.key -> "true") {
+        val plan = sql("SELECT * FROM testData").queryExecution.executedPlan
+        assert(!plan.isInstanceOf[AdaptiveSparkPlanExec])
+      }
+    }
+    assert(!testAppender.loggingEvents
+      .exists(msg => msg.getRenderedMessage.contains(
+        s"${SQLConf.ADAPTIVE_EXECUTION_ENABLED.key} is" +
+        s" enabled but is not supported for")))
+  }
 }