[SPARK-22883][ML] ML test for StructuredStreaming: spark.ml.feature, I-M#21042

jkbradley wants to merge 1 commit intoapache:branch-2.3apache/spark:branch-2.3from

jkbradley:SPARK-22883-part2-2.3backportjkbradley/spark:SPARK-22883-part2-2.3backportCopy head branch name to clipboard