SPARK-4660: Use correct class loader in JavaSerializer (copy of PR #3840...

... by Piotr Kolaczkowski)

Author: Jacek Lewandowski <lewandowski.jacek@gmail.com>

Closes #4113 from jacek-lewandowski/SPARK-4660-master and squashes the following commits:

a5e84ca [Jacek Lewandowski] SPARK-4660: Use correct class loader in JavaSerializer (copy of PR #3840 by Piotr Kolaczkowski)

core/src/main/scala/org/apache/spark/serializer/JavaSerializer.scala

@@ -92,7 +92,7 @@ private[spark] class JavaSerializerInstance(counterReset: Int, defaultClassLoade
   }
 
   override def deserializeStream(s: InputStream): DeserializationStream = {
-    new JavaDeserializationStream(s, Utils.getContextOrSparkClassLoader)
+    new JavaDeserializationStream(s, defaultClassLoader)
   }
 
   def deserializeStream(s: InputStream, loader: ClassLoader): DeserializationStream = {