Added better exit code checks for CIV execution.

[narmaku]

This allows the aws.sh script to finish gracefully in the event no test cases were collected because the filters used actually did not select any applicable test (e.g. "pub" marked tests for Image Builder internal CI).

Also added extra checks for infrastructure-related issues such as when CIV exits with code 100 (introduced by us to identify deployment issues).

[F-X64]

Changes look good to me. Added functionality makes sense. Approved!

Side note:
Long term I would suggest to use more functions and more involved conditional statements to make your flows easier to understand and maintain.

E.g. your switch could be rewritten as

run_civ_test() {
    ...
    $CIV_EXIT_CODE=$?
    ...
    case $CIV_EXIT_CODE in
        0)
            greenprint "💚 Success"
            exit 0
            ;;
        5)
            echo "❗ No tests were run"
            exit 0
            ;;
        100)
            redprint "❌ Failed (cloud deployment/destroy issues)"
            exit 1
            ;;
        *)
            redprint "❌ Failed (exit code: ${CIV_EXIT_CODE})"
            exit 1
            ;;
    esac

Just an extra thought.

[ConorC117]

LGTM too!