[SNAP-846][CLUSTER] Ensuring that Uncaught exceptions are handled in …

…the Snappy side and do not cause a system.exit (#2)

Instead of using SparkUncaughtExceptionHandler, executor now gets the uncaught exception handler and uses it to handle the exception. But if it is a local mode, it still uses the SparkUncaughtExceptionHandler

A test has been added in the Snappy side PR for the same.

core/src/main/scala/org/apache/spark/executor/Executor.scala

@@ -422,7 +422,12 @@ private[spark] class Executor(
           // Don't forcibly exit unless the exception was inherently fatal, to avoid
           // stopping other tasks unnecessarily.
           if (Utils.isFatalError(t)) {
-            SparkUncaughtExceptionHandler.uncaughtException(t)
+            if (!isLocal) {
+              Thread.getDefaultUncaughtExceptionHandler.
+                  uncaughtException(Thread.currentThread(), t)
+            } else {
+              SparkUncaughtExceptionHandler.uncaughtException(t)
+            }
           }
 
       } finally {