Fix HashStoreTests and move to Gtest (#43384)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/43384
Much like the FileStoreTests, the HashStoreTests were also run in a single blob and threw exceptions upon failure. This modularizes the test by separating each function into separate gtest test cases.
ghstack-source-id: 111690834
Test Plan: Confirmed that the tests pass on devvm.
Reviewed By: jiayisuse
Differential Revision: D23257579
fbshipit-source-id: 7e821f0e9ee74c8b815f06facddfdb7dc2724294
