Update default connectionMaxIdleTimeout for NettyNioAsyncClient

[zoewangg]

Description

Update default connectionMaxIdleTimeout for NettyNioAsyncClient to 5 seconds

Motivation and Context

#1122

Testing

Added unit tests.
Will run integ tests, stability tests.
Integ tests, stability tests passed

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist

• I have read the CONTRIBUTING document
• Local run of mvn install succeeds
• My code follows the code style of this project
• My change requires a change to the Javadoc documentation
• I have updated the Javadoc documentation accordingly
• I have read the README document
• I have added tests to cover my changes
• All new and existing tests passed
• A short description of the change has been added to the CHANGELOG
• My change is to implement 1.11 parity feature and I have updated LaunchChangelog

License

• I confirm that this pull request can be released under the Apache 2 license

[bmaizels]

Would have preferred us not to have to add a package protected accessor to prove it was working correctly, but accept that testing default configuration values with behavioral tests is not easy.