### What changes were proposed in this pull request?
Adds
```python
class _IsotonicRegressionBase(HasFeaturesCol, HasLabelCol, HasPredictionCol, HasWeightCol): ...
```
with related `Params` and uses it to replace `JavaPredictor` and `HasWeightCol` in `IsotonicRegression` base classes and `JavaPredictionModel,` in `IsotonicRegressionModel` base classes.
### Why are the changes needed?
Previous work (#25776) on [SPARK-28985](https://issues.apache.org/jira/browse/SPARK-28985) replaced `JavaEstimator`, `HasFeaturesCol`, `HasLabelCol`, `HasPredictionCol` in `IsotonicRegression` and `JavaModel` in `IsotonicRegressionModel` with newly added `JavaPredictor`:
e97b55d322/python/pyspark/ml/wrapper.py (L377)
and `JavaPredictionModel`
e97b55d322/python/pyspark/ml/wrapper.py (L405)
respectively.
This however is inconsistent with Scala counterpart where both classes extend private `IsotonicRegressionBase`
3cb1b57809/mllib/src/main/scala/org/apache/spark/ml/regression/IsotonicRegression.scala (L42-L43)
This preserves some of the existing inconsistencies (`model` as defined in [the official example](https://github.com/apache/spark/blob/master/examples/src/main/python/ml/isotonic_regression_example.py)), i.e.
```python
from pyspark.ml.regression impor IsotonicRegressionMode
from pyspark.ml.param.shared import HasWeightCol
issubclass(IsotonicRegressionModel, HasWeightCol)
# False
hasattr(model, "weightCol")
# True
```
as well as introduces a bug, by adding unsupported `predict` method:
```python
import inspect
hasattr(model, "predict")
# True
inspect.getfullargspec(IsotonicRegressionModel.predict)
# FullArgSpec(args=['self', 'value'], varargs=None, varkw=None, defaults=None, kwonlyargs=[], kwonlydefaults=None, annotations={})
IsotonicRegressionModel.predict.__doc__
# Predict label for the given features.\n\n .. versionadded:: 3.0.0'
model.predict(dataset.first().features)
# Py4JError: An error occurred while calling o49.predict. Trace:
# py4j.Py4JException: Method predict([class org.apache.spark.ml.linalg.SparseVector]) does not exist
# ...
```
Furthermore existing implementation can cause further problems in the future, if `Predictor` / `PredictionModel` API changes.
### Does this PR introduce any user-facing change?
Yes. It:
- Removes invalid `IsotonicRegressionModel.predict` method.
- Adds `HasWeightColumn` to `IsotonicRegressionModel`.
however the faulty implementation hasn't been released yet, and proposed additions have negligible potential for breaking existing code (and none, compared to changes already made in #25776).
### How was this patch tested?
- Existing unit tests.
- Manual testing.
CC huaxingao, zhengruifeng
Closes#26023 from zero323/SPARK-28985-FOLLOW-UP-isotonic-regression.
Authored-by: zero323 <mszymkiewicz@gmail.com>
Signed-off-by: Sean Owen <sean.owen@databricks.com>
8556710409