Should we add WatchBackwardsCompatibilityIT to master?

[nik9000]

In 6.x we have WatchBackwardsCompatibilityIT but master doesn't have this. It looks like a thing that we want though. I mean the big changes to watcher were in 6.0 but still, we could probably use some basic tests for it on upgrade to 7.0. Should we drag this file forward?

[elasticmachine]

Pinging @elastic/es-core-infra

[colings86]

@spinscale IS a test like this needed in master or do we have other tests now what cover these backwards compatibility areas?

[jasontedor]

We agreed that we should have BWC tests for Watcher (and, in general, all X-Pack functionality).