clang-format: [Java] Ignore C++-specific keywords

Before:
  public void union
  (Object o);
  public void struct
  (Object o);
  public void delete (Object o);

After:
  public void union(Object o);
  public void struct(Object o);
  public void delete(Object o);

Patch by Harry Terkelsen, thank you!

llvm-svn: 222357