clang-format: [Java] Support anonymous classes after = and return.

Before:
  A a = new A(){public String toString(){return "NotReallyA";
  }
  }
  ;

After:
  A a = return new A() {
    public String toString() {
      return "NotReallyA";
    }
  };

This fixes llvm.org/PR22878.

llvm-svn: 232042