AIDEGen: Collect the srcjar path of modules into module-info.json

By design doc: go/aidegen-doc-generate-R
In order to generate R.java of app modules, AIDEGen needs to build
the module. It might cause system.img oversized so we turn to build
the target srcjar file if it exists in module-info.json.

Build module-info.json without this change:
Build time: 1m47.227s
File size: 14,186,429 Bytes

Build module-info.json with this change:
Build time: 1m46.796s
File size: 14,614,470 Bytes

Bug: 132407603
Test: 1. m out/target/product/generic_x86_64/module-info.json
      2. by grep "target/common/obj/APPS/Settings_intermediates/aapt2.srcjar"
         in module-info.json.

Change-Id: I09c812aede0324bc38acbead0a863a85ae15b33e