AIDEGen: Collect apt generated sources

The Java compiler may generate sources when processing annotations.
These sources are currently not included in the IDE project model, which
results in unresolved symbols when using Hilt and other annotation
processors. These sources are not passed to the Java compiler for
compilation, so they cannot be handled like other Java module sources.

This change archives the generated sources and appends them to the
existing srcjar list in module_bp_java_deps.json.

Test: go test .
Test: Verified that module_bp_java_deps.json contained srcjar entry
Test:   with path/to/android_common/javac/anno.srcjar.
Test: Verified that IntelliJ can resolve generated symbols after
Test:   invoking aidegen.
Change-Id: I6a3011f9140fd25f785178baee0cd6074ad94600