(fs) Remove com.sun.nio.file.SensitivityWatchEventModifier

Summary

Remove com.sun.nio.file.SensitivityWatchEventModifier from the jdk.unsupported module.

Problem

Source code searches do not reveal any use of com.sun.nio.file.SensitivityWatchEventModifier so there is unlikely to be any point to retaining it.

Solution

Remove com.sun.nio.file.SensitivityWatchEventModifier and its use in the generic WatchService implementation sun.nio.fs.PollingWatchService.

Specification

There are no specification changes.