Preprocessed uses the same syntax of AIDL

Preprocessed file has been using a similar but different syntax.  Now,
it is using the same syntax with AIDL files with a couple of small
changes.

- Type decl can have qualified name.
  (interestinly, I only changed this for interface/enum)
- Interface can omit body(members) blocks.
  interface IFoo; // is simply an empty interface

Bug: 25479378
Test: aidl_unittests
Test: m
Change-Id: Icf5e4c321c469af00506c5ff14782251018d9d57
19 files changed