Trying to use dx.jar for the jar module name and dx for the
wrapper module name leads to the make side installing dx.jar.jar.
The separate names are only needed to make LOCAL_REQUIRED_MODULES
work. Make the names the same again, and use a manual dependency
from the installed location of the wrapper script to the installed
location of the jar to make sure that both get installed and that
the wrapper script timestamp is always as new as the jar.
Test: m -j checkbuild
Change-Id: Ibc8ce9d24ed770e9a270fb8eaa8fe1b427a382a7