Collect file delta metrics for java and kotlin compiles

- Update the kotlinc and javac build rules to generate changed file
  metrics.
- Upload the aggregated metrics at build completion.
- Also fixes parsing of --inputs_file and --target to be consistent with
  existing use cases.

Bug: b/365537477
Test: manual, TH
Change-Id: I48efe06917baa98081e18b6351b63a624b55dba8