[SPARK-8393][STREAMING] JavaStreamingContext#awaitTermination() throws non-declared InterruptedException

## What changes were proposed in this pull request?

`JavaStreamingContext.awaitTermination` methods should be declared as `throws[InterruptedException]` so that this exception can be handled in Java code. Note this is not just a doc change, but an API change, since now (in Java) the method has a checked exception to handle. All await-like methods in Java APIs behave this way, so seems worthwhile for 2.0.

## How was this patch tested?

Jenkins tests

Author: Sean Owen <sowen@cloudera.com>

Closes #12418 from srowen/SPARK-8393.