Move constant and type kind enums out of the ast package

They're going to be re-used during analysis, so they don't belong in ast.

MOE_MIGRATED_REVID=131329025
5 files changed
tree: 3748e3f2440b768dbab5a12406ed78f6e727f0f9
  1. java/
  2. javatests/
  3. pom.xml