Correctness Testing 2.0

[fredjoonpark]

Issue #, if available:

Description of changes:

Removed our deprecated correctness test suite in place of a new approach for correctness testing.

• Added a new class Mockmetheus to send remote operations from Prometheus using snappy-encoded payloads. The previous testing approach included bringing up a Prometheus instance to seed initial testing data to run queries. This introduced conflicts as queries would fetch data from across both local and remote (Amazon Timestream) sources.
  Also, we had test cases that included functions and certain operators using client-side logic (which are not in scope of the Connector). It now focuses exclusively on the correctness of remote read and write operations.

• Correctness tests are set up as a separate module since the underlying Prometheus dependency is using v2.5.0, and the parser was introduced as a package in a later released version.

• Fixed bug where write requests without labels returned 500 instead of 422. While Prometheus always includes labels in remote writes, our Connector now handles the edge case properly.

• Updated error codes to better reflect "not found" scenarios:

  • MissingDatabaseWithWriteError: Changed from 400 to 404
  • MissingTableWithWriteError: Changed from 400 to 404

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[trevorbonas]

Reviewed internally.

[forestmvey]

Thanks for the fixes!