## What changes were proposed in this pull request?
Methods `numClasses` and `numFeatures` in LinearSVCModel are already usable by inheriting `JavaClassificationModel`
we should not explicitly add them.

## How was this patch tested?
existing tests

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #16727 from zhengruifeng/nits_in_linearSVC.