[SPARK-13423][HOTFIX] Static analysis fixes for 2.x / fixed for Scala 2.10, again

## What changes were proposed in this pull request?

Fixes (another) compile problem due to inadvertent use of Option.contains, only in Scala 2.11

## How was this patch tested?

Jenkins tests

Author: Sean Owen <sowen@cloudera.com>

Closes #11496 from srowen/SPARK-13423.3.

core/src/test/scala/org/apache/spark/scheduler/TaskResultGetterSuite.scala

@@ -243,7 +243,7 @@ class TaskResultGetterSuite extends SparkFunSuite with BeforeAndAfter with Local
     val resAfter = captor.getValue
     val resSizeBefore = resBefore.accumUpdates.find(_.name == Some(RESULT_SIZE)).flatMap(_.update)
     val resSizeAfter = resAfter.accumUpdates.find(_.name == Some(RESULT_SIZE)).flatMap(_.update)
-    assert(resSizeBefore.contains(0L))
+    assert(resSizeBefore.exists(_ == 0L))
     assert(resSizeAfter.exists(_.toString.toLong > 0L))
   }