Build Java aidl w/ '-b'.

As it turns out, AIDL originally passed and returned success
when it was asked to compile an unstructured parcelable even
though no output files were created.

The build system currently can't handle this because it is
expecting outputs here, so I am adding this argument here
which will cause the compiler to exit and error earlier as
expected.

Notice also that the make implementation of the AIDL build
system also passes in this argument.

Test: m framework (which invokes this many times)
Bug: N/A
Change-Id: Ia9b5280dc3593756784035a523399545c9947d80

java/java.go

@@ -631,7 +631,8 @@ func (j *Module) aidlFlags(ctx android.ModuleContext, aidlPreprocess android.Opt
 	aidlIncludes = append(aidlIncludes,
 		android.PathsForSource(ctx, j.deviceProperties.Aidl.Include_dirs)...)
 
-	var flags []string
+	flags := []string{"-b"}
+
 	if aidlPreprocess.Valid() {
 		flags = append(flags, "-p"+aidlPreprocess.String())
 	} else {