[Hot Fix #469] Fix flaky test in SparkListenerSuite

The two modified tests may fail if the race condition does not bid in our favor...

Author: Andrew Or <andrewor14@gmail.com>

Closes #516 from andrewor14/stage-info-test-fix and squashes the following commits:

b4b6100 [Andrew Or] Add/replace missing waitUntilEmpty() calls to listener bus

(cherry picked from commit 4b2bab1d08a6b790be94717bbdd643d896d85c16)
Signed-off-by: Reynold Xin <rxin@apache.org>
Update Java api for setJobGroup with interruptOnCancel

Also adds a unit test.

Author: Aaron Davidson <aaron@databricks.com>

Closes #522 from aarondav/cancel2 and squashes the following commits:

565c253 [Aaron Davidson] Update Java api for setJobGroup with interruptOnCancel
65b33d8 [Aaron Davidson] Add unit test for Thread interruption on cancellation

(cherry picked from commit d485eecb7233dd339ae85a6f58f1c0686dd2037d)
Signed-off-by: Reynold Xin <rxin@apache.org>
Mark all fields of EdgePartition, Graph, and GraphOps transient

These classes are only serializable to work around closure capture, so their fields should all be marked `@transient` to avoid wasteful serialization.

This PR supersedes apache/spark#519 and fixes the same bug.

Author: Ankur Dave <ankurdave@gmail.com>

Closes #520 from ankurdave/graphx-transient and squashes the following commits:

6431760 [Ankur Dave] Mark all fields of EdgePartition, Graph, and GraphOps `@transient`

(cherry picked from commit 1d6abe3a4b58f28fc4e0e690e02c19b2568ce1ee)
Signed-off-by: Reynold Xin <rxin@apache.org>