Update automation-content to account for deltas in (vendor-furnished) CentOS 9 Stream bootstrap images

[ferricoxide]

1. Updates spel/scripts/amigen9-build.sh and spel/scripts/builder-prep-9.sh to reflect correct, default repo-names.
2. Adds/corrects builder test-definitions

[ferricoxide]

CentOS 9 Stream logic vetted (from CodeBuild spel-commercial job-number 266):

amazon-ebs.minimal-centos-7-hvm: ======================= 18 passed, 13 skipped in 30.64s ========================
amazon-ebs.minimal-centos-8stream-hvm: ======================= 17 passed, 14 skipped in 16.69s ========================
amazon-ebs.minimal-centos-9stream-hvm: ======================= 13 passed, 18 skipped in 20.06s ========================
amazon-ebs.minimal-ol-8-hvm: ======================= 17 passed, 14 skipped in 41.61s ========================
amazon-ebs.minimal-ol-9-hvm: ======================= 13 passed, 18 skipped in 14.28s ========================
amazon-ebs.minimal-rhel-7-hvm: ======================= 18 passed, 13 skipped in 41.20s ========================
amazon-ebs.minimal-rhel-8-hvm: ======================= 17 passed, 14 skipped in 14.35s ========================
amazon-ebs.minimal-rhel-9-hvm: ======================= 13 passed, 18 skipped in 16.04s ========================

[ferricoxide]

There's some kind of bad merge history here. The files in the changeset as depicted by GitHub show changes from the prior OL8 fixes.

Bleah. After I noticed that the OL9 changes had been approved and merged, I rebased my branch from upstream/master to ensure I could run an "all builders" test (success-output noted in my prior comment). Not why the extra grumph.

It shouldn't create double entries, though?

Any rate, I'll see if I can clean up my branch.