[KYUUBI #4150] Support to execute Scala statement synchronized to prevent conflicts

### _Why are the changes needed?_

Support to execute Scala statement synchronized to prevent conflicts, because they share the same `spark.repl.class.outputDir`.

### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible

- [ ] Add screenshots for manual tests if appropriate

- [x] [Run test](https://kyuubi.apache.org/docs/latest/develop_tools/testing.html#running-tests) locally before make a pull request

Closes #4150 from turboFei/lock_scala.

Closes #4150

f11f12a26 [fwang12] lock more
d7a9fe8ed [fwang12] remove conf
d4175827e [fwang12] update docs
c1524a7fc [fwang12] lock required
a6e663be7 [fwang12] lock scala

Authored-by: fwang12 <fwang12@ebay.com>
Signed-off-by: fwang12 <fwang12@ebay.com>

externals/kyuubi-spark-sql-engine/src/main/scala/org/apache/kyuubi/engine/spark/repl/KyuubiSparkILoop.scala

@@ -18,6 +18,7 @@
 package org.apache.kyuubi.engine.spark.repl
 
 import java.io.{ByteArrayOutputStream, File}
+import java.util.concurrent.locks.ReentrantLock
 
 import scala.tools.nsc.Settings
 import scala.tools.nsc.interpreter.IR
@@ -32,10 +33,11 @@ private[spark] case class KyuubiSparkILoop private (
     spark: SparkSession,
     output: ByteArrayOutputStream)
   extends SparkILoop(None, new JPrintWriter(output)) {
+  import KyuubiSparkILoop._
 
   val result = new DataFrameHolder(spark)
 
-  private def initialize(): Unit = {
+  private def initialize(): Unit = withLockRequired {
     settings = new Settings
     val interpArguments = List(
       "-Yrepl-class-based",
@@ -98,7 +100,7 @@ private[spark] case class KyuubiSparkILoop private (
 
   def clearResult(statementId: String): Unit = result.unset(statementId)
 
-  def interpretWithRedirectOutError(statement: String): IR.Result = {
+  def interpretWithRedirectOutError(statement: String): IR.Result = withLockRequired {
     Console.withOut(output) {
       Console.withErr(output) {
         this.interpret(statement)
@@ -120,4 +122,12 @@ private[spark] object KyuubiSparkILoop {
     iLoop.initialize()
     iLoop
   }
+
+  private val lock = new ReentrantLock()
+  private def withLockRequired[T](block: => T): T = {
+    try {
+      lock.lock()
+      block
+    } finally lock.unlock()
+  }
 }