veyron.io/veyron/veyron2/vdl/codegen/java: Handle unnamed VDL arguments.
veyron.io/veyron/veyron2/vdl/codegen/java: Handle unnamed VDL arguments.

Change-Id: I620ccac725cd840b10ac65b505223cec117fed3d

vanadium/go.v23,vanadium/go.v23,vanadium/go.v23