listenablefuture and failureaccess are incompatible with Java's package module system

[shs96c]

When included in the module-path the listenablefuture and failureaccess jars introduce classes that are also in the guava jar, causing a "split package", which causes all manner of chaos.

Although not including these jars on the module path might be possible, it's hard to determine in an automated way whether or not to include any random jar on the module path or not.

Since these jars should also have a module name, the better solution would be to move the classes within these jars to unique packages, thus avoiding the problem of a split package in the first place.

[cpovirk]

The failureaccess overlap is a bug fixed in 27.0.1 -- sorry about that.

With the listenablefuture overlap, users may have to manually exclude listenablefuture. We've set things up so that this is safe.

We may still make changes here. To keep that discussion in one place, we have #3320 for that.