Support skipping tests that don't actually hold data

[joehandzik]

Code originated from Craig Tierney at NVIDIA

Signed-Off-By: Joe Handzik [email protected]

Why we need this PR?

Pick one, remove the rest

• Refactoring to improve handling of datasets for RN50 Pipeline test

What happened in this PR?

• What solution was applied: [ When test data is nonexistent for whatever reason, the test is skipped, avoiding a failure ]
• Affected modules and functionalities: [ RN50 Pipeline test ]
• Key points relevant for the review: [ ]
• Validation and testing: [ Run internally for performance comparison purposes ]
• Documentation (including examples): [ N/A]

JIRA TASK: [NA]