make ProcessGroup.Options.timeout argument private in python (#56531)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/56531
per discussions in
https://github.com/pytorch/pytorch/pull/53663/files#r593409009, we need
to make sure our API not confusing user by passing in both timeout in
argument and timeout in processgroup.options. This PR tries to make the
`ProcessGroup.Options.timeout` be a private field, and only be used in
our test utils, for both `init_process_group` and `new_group`, we still
allow user pass `timeout` as a separate argument. Since
`ProcessGroupGloo.Options` only have a `timeout` config, both functions
will not allow passing in options for the GLOO backend.
This way we still preserve the only `timeout` API, and only allow user
to use `ProcessGroupNCCL.Options` when needed.
cc pritamdamania87 rohan-varma
Test Plan: Imported from OSS
Reviewed By: rohan-varma
Differential Revision: D27893395
Pulled By: wanchaol
fbshipit-source-id: cdd29c84648002226ef3d9f9f3ea67b795e64bc5
