[SPARK-22001][ML][SQL] ImputerModel can do withColumn for all input columns at one pass

## What changes were proposed in this pull request?

SPARK-21690 makes one-pass `Imputer` by parallelizing the computation of all input columns. When we transform dataset with `ImputerModel`, we do `withColumn` on all input columns sequentially. We can also do this on all input columns at once by adding a `withColumns` API to `Dataset`.

The new `withColumns` API is for internal use only now.

## How was this patch tested?

Existing tests for `ImputerModel`'s change. Added tests for `withColumns` API.

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #19229 from viirya/SPARK-22001.