[SPARK-11820][ML][PYSPARK] PySpark LiR & LoR should support weightCol

[SPARK-7685](https://issues.apache.org/jira/browse/SPARK-7685) and [SPARK-9642](https://issues.apache.org/jira/browse/SPARK-9642) have already supported setting weight column for ```LogisticRegression``` and ```LinearRegression```. It's a very important feature, PySpark should also support. mengxr

Author: Yanbo Liang <ybliang8@gmail.com>

Closes #9811 from yanboliang/spark-11820.