Add option to compile dex for a Java library

Currently Soong will only compile a Java library into dex if the
library has device support and is installable. For our use case of
inspecting the dex at build time this is not sufficient. Add a new
"compile_dex" device property which forces the creation of a dex
rule. In this case, the class jar remains the output file of the
module.

Bug: 79409988
Test: on related CL
Change-Id: Ia908a47148a03a0bdb0da4315cce6efc86c51865