(BE) Refactor get-test-times-from-S3 into s3_stat_parser (#54808)
Summary:
Moves more s3 parsing code to s3_stat_parser.py. This is another step in modularizing the parsing code more correctly. I will also be using this exact function in future slowTest code.
Also replaces some Any's in the code to be Report.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/54808
Test Plan:
.pytorch-test-times generated before the code and after this code is the same.
CI should pass, specifically the test tools GHA.
Reviewed By: walterddr
Differential Revision: D27375783
Pulled By: janeyx99
fbshipit-source-id: bec28551668b2eb3fdd60d802200993e493eac83
