Why? At some point, presumably after
                   https://github.com/google/guava/commit/e06a8cec65815599e510d7f9c1ea9d2a8eaa438a,
                   builds with JDK8 began failing animal-sniffer with the error:

                   Failed to check signatures: Bad class file .../CollectionFuture$ListFuture.class

                   One way of dealing with that would be to disable

              <!--
                To avoid "java.io.IOException: User limit of inotify watches reached" under JDK10.
                Presumably we don't need inotify, since we don't intend to change files during the
                build?
                -->
              <extraJvmArgs>-Dgwt.watchFileChanges=false</extraJvmArgs>
            </configuration>
          </execution>
          <!--