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!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@222357 91177308-0d34-0410-b5e6-96231b3b80d8