[SPARK-11378][STREAMING] make StreamingContext.awaitTerminationOrTimeout return properly

This adds a failing test checking that `awaitTerminationOrTimeout` returns the expected value, and then fixes that failing test with the addition of a `return`.

tdas zsxwing

Author: Nick Evans <me@nicolasevans.org>

Closes #9336 from manygrams/fix_await_termination_or_timeout.