Allow "cross-module-jars" to be passed to dependency-mapper.

With this, dependency-mapper can accept a list of other jars that the
source under analysis depends upon, and it will include a list of
classes from those jars that source references.

: Fix
  - Fix DependencyMapperTest
  - Various formatting cleanups

Bug: 418279584
Test: m SystemUI-core
Change-Id: I7e4e395d8f4360af389caf6575404ed92d69da99