Adjust upgrade_snapshots to new snapper ls output

[jknphy]

Adjust test to new snapper ls output. Regex updated to be able to move 4 or 5 columns to the right.

• Related ticket: https://progress.opensuse.org/issues/42635
• Verification run (still running):
  • Tumbleweed-kde+system_performance-upgrade_snapshots
  • Leap15.1-kde+system_performance-upgrade_snapshots

[asdil12]

Does this already deal with different column orderings (see #5995)?

[jknphy]

It doesn't, but we have a different implementation for every snapper test, unfortunately. In this case I don't see the point in my opinion, it will just over-complicate the test.