Though `.watch` actually ran decent test coverage of push mode,
JaCoCo did not show `Watcher` since all the tests ran on agents in another JVM.
Adding a mode to run on-controller since people do sometimes do that,
and it should show up in JaCoCo,
and log messages from the watcher go to test output which is helpful.

…un e.g. `mvn test -Dtest="BourneShellScriptTest#binaryCaching[0: ON_CONTROLLER]"`

…ion of `binaryPath`

…ATIVE`