libart-compiler cleanup

- Move compile-time code to src/compiler and libart-compiler
  OatWriter, ImageWriter, ElfWriter, ElfFixup, ElfStripper, stub generation
- Move ClassReference and MethodReference to remove MethodVerifier dependency on CompilerDriver
- Move runtime_support_llvm.cc out of src/compiler and next to runtime_support.cc
- Change dex2oat and gtests to directly depend on libart-compiler
- Move non-common definitions from Android.common.mk to more specific makefiles
- Add LOCAL_ADDITIONAL_DEPENDENCIES on appropriate makefiles

Change-Id: I897027e69945914128f21f317a92caf9255bc600