Update compare_set implementation for FileStore and HashStore (#57175)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/57175
Update other Store implementations to add the value when current value is empty to match the amendment made to TCPStore (#55636). Added test to cover this case.
Test:
`pytest -vs test/distributed/test_c10d_common.py -k compare_set`
Test Plan: Imported from OSS
Reviewed By: cbalioglu
Differential Revision: D28069380
Pulled By: H-Huang
fbshipit-source-id: eac703edb41faee32a4e7cda61107e2a0e726326
