test: add e2e tests for sync expression behavior

[phani-srikar]

Description of changes

Add e2e tests that cover this advanced use-case where a Sync query using GSI will query the base table using that GSI instead of a scan operation.

Issue #, if available

Description of how you validated changes

Successfully ran these e2e tests locally

Checklist

• PR description included
• yarn test passes
• Tests are changed or added
• Relevant documentation is changed or added (and PR referenced)
• New AWS SDK calls or CloudFormation actions have been added to relevant test and service IAM policies

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-commenter]

Codecov Report

Merging #830 (a47d8fc) into main (e0d7540) will not change coverage.
The diff coverage is n/a.

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  Lines       18356    18356           
  Branches     4453     4453           
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  Hits        11615    11615           
  Misses       6131     6131           
  Partials      610      610           

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[AaronZyLee]

LGTM. Just have one question on how to identify the query instead of scan from the e2e tests. Is it indicated by the timestamp?

[phani-srikar]

From my discussion with Ivan, there is no easy way to identify that unless we have logging enabled for the resolvers. However, the tests added here cover the part of the resolver that is known to generate a Query expression like using filters on GSI.