SPARK-1929 DAGScheduler suspended by local task OOM

DAGScheduler does not handle local task OOM properly, and will wait for the job result forever.

Author: Zhen Peng <zhenpeng01@baidu.com>

Closes #883 from zhpengg/bugfix-dag-scheduler-oom and squashes the following commits:

76f7eda [Zhen Peng] remove redundant memory allocations
aa63161 [Zhen Peng] SPARK-1929 DAGScheduler suspended by local task OOM