Description of problem:
When using reposync to sync a repo using the --newest option, modules that share a name, but have multiple streams only sync the most recent stream instead of syncing the newest package from both streams. As an example, the following are the available perl module streams:

perl                             5.24                     common [d], minimal                                  Practical Extraction and Report Language                                      

perl                             5.26 [d]                 common [d], minimal                                  Practical Extraction and Report Language                                      

If you use reposync with --newest on RHEL 8, you end up only syncing the 5.26 stream, and you don't get any packages from the 5.24 stream.

Version-Release number of selected component (if applicable):
yum-utils-4.0.8-3.el8.noarch

How reproducible:
Always

Steps to Reproduce:
1. # reposync --repoid=rhel-8-for-x86_64-appstream-rpms --newest

Actual results:
The reposync command only obtains the newest stream instead of the newest package from each stream

Expected results:
The reposync command should obtain the newest package from each stream, instead of only obtaining the newest stream

Additional info:
It should be noted, that even fixing this, modules will still be a bit odd with --newest. The reason being, that in order to have module metadata you'll have to reposync with the --download-metadata option still, and in that situation you'll have metadata for packages that you don't actually have downloaded. This shouldn't prove to cause any dependency issues in the resulting synced repo though as far as I can tell.