[SPARK-20714][SS] Fix match error when watermark is set with timeout = no...

[SPARK-20714][SS] Fix match error when watermark is set with timeout = no timeout / processing timeout

## What changes were proposed in this pull request?

When watermark is set, and timeout conf is NoTimeout or ProcessingTimeTimeout (both do not need the watermark), the query fails at runtime with the following exception.
```
MatchException: Some(org.apache.spark.sql.catalyst.expressions.GeneratedClass$SpecificPredicate1a9b798e) (of class scala.Some)
    org.apache.spark.sql.execution.streaming.FlatMapGroupsWithStateExec$$anonfun$doExecute$1.apply(FlatMapGroupsWithStateExec.scala:120)
    org.apache.spark.sql.execution.streaming.FlatMapGroupsWithStateExec$$anonfun$doExecute$1.apply(FlatMapGroupsWithStateExec.scala:116)
    org.apache.spark.sql.execution.streaming.state.package$StateStoreOps$$anonfun$1.apply(package.scala:70)
    org.apache.spark.sql.execution.streaming.state.package$StateStoreOps$$anonfun$1.apply(package.scala:65)
    org.apache.spark.sql.execution.streaming.state.StateStoreRDD.compute(StateStoreRDD.scala:64)
```

The match did not correctly handle cases where watermark was defined by the timeout was different from EventTimeTimeout.

## How was this patch tested?
New unit tests.

Author: Tathagata Das <tathagata.das1565@gmail.com>

Closes #17954 from tdas/SPARK-20714.