Add flag to make sure we don't validate checksum twice

[zoewangg]

Description

Add checksumValidated flag to ChecksumValidatingInputStream to make s we don't validate twice

Motivation and Context

Fixes #873

Testing

All s3 integ 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
• 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