[refmt] Formatting of trailing comments in for-loops is not idempotent

[kyldvs]

(what happens to the comment is also probably a bug)

Start here: (try reason link)

for (i in 0 to 1) {
  /* comment */
  print_newline();
  /* comment */
  print_newline()
  /* comment */
};

();

After first refmt:

for (i in 0 to 1)
  {
    /* comment */
    print_newline();
    /* comment */
    print_newline()
  };
  /* comment */

();

After second refmt:

for (i in 0 to 1) {
  /* comment */
  print_newline();
  /* comment */
  print_newline()
};

/* comment */
();

[jordwalke]

Remaining (more rare) issue tracked here: #1781