[SPARK-18520][ML] Add missing setXXXCol methods for BisectingKMeansModel and GaussianMixtureModel

## What changes were proposed in this pull request?
add `setFeaturesCol` and `setPredictionCol` for BiKModel and GMModel
add `setProbabilityCol` for GMModel
## How was this patch tested?
existing tests

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #15957 from zhengruifeng/bikm_set.

mllib/src/main/scala/org/apache/spark/ml/clustering/BisectingKMeans.scala

@@ -98,6 +98,14 @@ class BisectingKMeansModel private[ml] (
     copied.setSummary(trainingSummary).setParent(this.parent)
   }
 
+  /** @group setParam */
+  @Since("2.1.0")
+  def setFeaturesCol(value: String): this.type = set(featuresCol, value)
+
+  /** @group setParam */
+  @Since("2.1.0")
+  def setPredictionCol(value: String): this.type = set(predictionCol, value)
+
   @Since("2.0.0")
   override def transform(dataset: Dataset[_]): DataFrame = {
     transformSchema(dataset.schema, logging = true)

mllib/src/main/scala/org/apache/spark/ml/clustering/GaussianMixture.scala

@@ -87,6 +87,18 @@ class GaussianMixtureModel private[ml] (
     @Since("2.0.0") val gaussians: Array[MultivariateGaussian])
   extends Model[GaussianMixtureModel] with GaussianMixtureParams with MLWritable {
 
+  /** @group setParam */
+  @Since("2.1.0")
+  def setFeaturesCol(value: String): this.type = set(featuresCol, value)
+
+  /** @group setParam */
+  @Since("2.1.0")
+  def setPredictionCol(value: String): this.type = set(predictionCol, value)
+
+  /** @group setParam */
+  @Since("2.1.0")
+  def setProbabilityCol(value: String): this.type = set(probabilityCol, value)
+
   @Since("2.0.0")
   override def copy(extra: ParamMap): GaussianMixtureModel = {
     val copied = copyValues(new GaussianMixtureModel(uid, weights, gaussians), extra)