Publish timeout issues with tests

[ehuss]

The following tests are blocking for a minute waiting for a publish that never finishes:

• alt_registry::publish_to_alt_registry
• alt_registry::publish_with_crates_io_dep
• alt_registry::publish_with_registry_dependency

This is a multi-part issue:

1. Fix these tests so they don't block.
2. Change these tests so that they use with_stderr to validate their output (which would have caught this regression).
3. Avoid the "hack" added in #11388. I'm not sure what the best approach would be here. One would be to spin up the publish server so that instead of cargo just writing the new file, it would actually speak HTTP. Another is to disable the delay. Probably some other options are viable as well. (And similarly update those tests to validate their output.)
4. Implement something to prevent this from happening in the future. I'm not sure about the best approach here, but perhaps something like if cargo publish fails to wait for the propagation, to fail the test.

cc @arlosi

[epage]

sigh when originally implementing this, the timeouts were hard to find and deal with in tests. I appreciate cargo nextest highlights overly long test cases and wish that was more generally available.

[Rustin170506]

@rustbot claim I am working on this.