[SPARK-20764][ML][PYSPARK][FOLLOWUP] Fix visibility discrepancy with...

[SPARK-20764][ML][PYSPARK][FOLLOWUP] Fix visibility discrepancy with numInstances and degreesOfFreedom in LR and GLR - Python version

## What changes were proposed in this pull request?
Add test cases for PR-18062

## How was this patch tested?
The existing UT

Author: Peng <peng.meng@intel.com>

Closes #18068 from mpjlu/moreTest.