Update integration test to include sample order comparison

[karan6181]

Description of changes:

• As part of testing streaming feature regularly to capture any regression, I had to add the below changes to make certain test working, such as.
  • Validating number of files locally
  • Validating the epoch iteration time
  • Validating the sample orders
• More details is in PR https://github.com/mosaicml/testing/pull/43

Issue #, if available:

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[snarayan21]

lgtm, just had some clarifying questions