[jvm] Flag some methods as sideways.

This suppresses some warnings and brings this into line with
other back-ends.
[jvm] Get rid of *java-back-end*.
[jvm] Exclude format-to-string from common-dylan.
[jvm] Remove unused makefile stuff.
[jvm] Use dylan library.

The dylan library provides the machine-word-lowlevel module.
[jvm] stub out missing java-packages.dylan.
[jvm] Remove some outdated / unused slots.
[jvm] Fix some warnings.