Umbrella build targets to help engineers verify build

With this change, by choosing the right build target, you can reduce
significant verification build time:
If you are working on the framework, "make target-java" sounds enough;
if you are working on native target code, "make target-native" saves
your time by not building the Java code.
This will help reduce uncaught breakges for by default not everything
is built now.

Change-Id: I5a7c82d3f6372db03bea76155c8d6cc63d988eae
2 files changed