[21pt] Change location for test_case validation data

[RobHanna-NOAA]

Our current test_case folders have validation_data folders mixed in with folders that have our analysis alpha test results. This has created a number of problems over the years and we need the raw validation_data separate from the output data.

Recently, a bunch of folders inside the test_case folder were deleted in error while cleaning up output alpha test data, but we were able to recover data from S3.

While the current 5 validation folder continue to exist where they are, a new folder in EFS called test_case_validation_data has been created and populated.

Please look through all tools including synthesize_test_cases.py and change the pathing to look for the new test_case_valdiation_data for input and keep the alpha testing output data as it is. Not sure if more places than just synth look for this folder specifically for validation data, so check other tools as well.

[mluck]

This will require data/get_sample_data.py to be updated in the dev-sample-data branch (#1178).