Stop installing java goo into system.img
We need to tighten our belts a little bit more for the maguro. The way we've been killing java stuff so far is by whacking Android.mk's, but that's a pretty heavyweight solution and is going to cause a bit of some merge pain.
Another way I thought of to do this is replace the core make rules for .java/.dex etc by no-op commands. Basically rip out all the java-related rules. I'm not sure how hard this would be, but it's a more surgical strike. Unfortunately though, that doesn't help with whacking JNI .cpp's.
Needs investigation.
Perhaps just removing the build rule for .jar is the easiest way to start.
This issue is a bit overly general. Will break future work into items tracked by the "decaf" label.
See also #142