[SPARK-12424][ML] The implementation of ParamMap#filter is wrong.

ParamMap#filter uses `mutable.Map#filterKeys`. The return type of `filterKey` is collection.Map, not mutable.Map but the result is casted to mutable.Map using `asInstanceOf` so we get `ClassCastException`.
Also, the return type of Map#filterKeys is not Serializable. It's the issue of Scala (https://issues.scala-lang.org/browse/SI-6654).

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #10381 from sarutak/SPARK-12424.