fix: isCometEnabled name conflict (apache#1569)

## Which issue does this PR close?

## Rationale for this change

We have a name collision on `isCometEnabled`

```
CometSparkSessionExtensions
private[comet] def isCometEnabled(conf: SQLConf): Boolean = {
```
and
```
SQLTestUtilsBase
protected def isCometEnabled: Boolean = SparkSession.isCometEnabled
```

causing build issues depending on which one gets picked up
```
[ERROR] /workspace/spark/src/test/scala/org/apache/comet/CometSparkSessionExtensionsSuite.scala:34: Boolean does not take parameters
[ERROR] /workspace/spark/src/test/scala/org/apache/comet/CometSparkSessionExtensionsSuite.scala:42: Boolean does not take parameters
[ERROR] /workspace/spark/src/test/scala/org/apache/comet/CometSparkSessionExtensionsSuite.scala:47: Boolean does not take parameters
```

## What changes are included in this PR?

Renamed one to `isCometLoaded`

## How are these changes tested?

CI

Author: kazuyukitanimura

spark/src/main/scala/org/apache/comet/CometSparkSessionExtensions.scala

@@ -55,7 +55,7 @@ import org.apache.spark.sql.types.{DoubleType, FloatType}
 
 import org.apache.comet.CometConf._
 import org.apache.comet.CometExplainInfo.getActualPlan
-import org.apache.comet.CometSparkSessionExtensions.{createMessage, getCometBroadcastNotEnabledReason, getCometShuffleNotEnabledReason, isANSIEnabled, isCometBroadCastForceEnabled, isCometEnabled, isCometExecEnabled, isCometJVMShuffleMode, isCometNativeShuffleMode, isCometScan, isCometScanEnabled, isCometShuffleEnabled, isSpark40Plus, shouldApplySparkToColumnar, withInfo, withInfos}
+import org.apache.comet.CometSparkSessionExtensions.{createMessage, getCometBroadcastNotEnabledReason, getCometShuffleNotEnabledReason, isANSIEnabled, isCometBroadCastForceEnabled, isCometExecEnabled, isCometJVMShuffleMode, isCometLoaded, isCometNativeShuffleMode, isCometScan, isCometScanEnabled, isCometShuffleEnabled, isSpark40Plus, shouldApplySparkToColumnar, withInfo, withInfos}
 import org.apache.comet.parquet.{CometParquetScan, SupportsComet}
 import org.apache.comet.rules.RewriteJoin
 import org.apache.comet.serde.OperatorOuterClass.Operator
@@ -93,8 +93,8 @@ class CometSparkSessionExtensions
 
   case class CometScanRule(session: SparkSession) extends Rule[SparkPlan] {
     override def apply(plan: SparkPlan): SparkPlan = {
-      if (!isCometEnabled(conf) || !isCometScanEnabled(conf)) {
-        if (!isCometEnabled(conf)) {
+      if (!isCometLoaded(conf) || !isCometScanEnabled(conf)) {
+        if (!isCometLoaded(conf)) {
           withInfo(plan, "Comet is not enabled")
         } else if (!isCometScanEnabled(conf)) {
           withInfo(plan, "Comet Scan is not enabled")
@@ -975,8 +975,8 @@ class CometSparkSessionExtensions
         }
       }
 
-      // We shouldn't transform Spark query plan if Comet is disabled.
-      if (!isCometEnabled(conf)) return plan
+      // We shouldn't transform Spark query plan if Comet is not loaded.
+      if (!isCometLoaded(conf)) return plan
 
       if (!isCometExecEnabled(conf)) {
         // Comet exec is disabled, but for Spark shuffle, we still can use Comet columnar shuffle
@@ -1172,9 +1172,9 @@ object CometSparkSessionExtensions extends Logging {
   }
 
   /**
-   * Checks whether Comet extension should be enabled for Spark.
+   * Checks whether Comet extension should be loaded for Spark.
    */
-  private[comet] def isCometEnabled(conf: SQLConf): Boolean = {
+  private[comet] def isCometLoaded(conf: SQLConf): Boolean = {
     if (isBigEndian) {
       logInfo("Comet extension is disabled because platform is big-endian")
       return false

spark/src/test/scala/org/apache/comet/CometSparkSessionExtensionsSuite.scala

@@ -27,24 +27,24 @@ class CometSparkSessionExtensionsSuite extends CometTestBase {
 
   import CometSparkSessionExtensions._
 
-  test("isCometEnabled") {
+  test("isCometLoaded") {
     val conf = new SQLConf
 
     conf.setConfString(CometConf.COMET_ENABLED.key, "false")
-    assert(!isCometEnabled(conf))
+    assert(!isCometLoaded(conf))
 
     // Since the native lib is probably already loaded due to previous tests, we reset it here
     NativeBase.setLoaded(false)
 
     conf.setConfString(CometConf.COMET_ENABLED.key, "true")
     val oldProperty = System.getProperty("os.name")
     System.setProperty("os.name", "foo")
-    assert(!isCometEnabled(conf))
+    assert(!isCometLoaded(conf))
 
     System.setProperty("os.name", oldProperty)
 
     conf.setConf(SQLConf.PARQUET_INT96_TIMESTAMP_CONVERSION, true)
-    assert(!isCometEnabled(conf))
+    assert(!isCometLoaded(conf))
 
     // Restore the original state
     NativeBase.setLoaded(true)