[SPARK-8290] spark class command builder need read SPARK_JAVA_OPTS and SPARK_DRIVER_MEMORY properly

SPARK_JAVA_OPTS was missed in reconstructing the launcher part, we should add it back so process launched by spark-class could read it properly. And so does `SPARK_DRIVER_MEMORY`.

The missing part is [here](https://github.com/apache/spark/blob/1c30afdf94b27e1ad65df0735575306e65d148a1/bin/spark-class#L97).

Author: WangTaoTheTonic <wangtao111@huawei.com>
Author: Tao Wang <wangtao111@huawei.com>

Closes #6741 from WangTaoTheTonic/SPARK-8290 and squashes the following commits:

bd89f0f [Tao Wang] make sure the memory setting is right too
e313520 [WangTaoTheTonic] spark class command builder need read SPARK_JAVA_OPTS