`parse_with_comments` miss-allocating comment

[brodieG]

  expect_equal(
    fun1(a, b, c, d, e, f), # internal comment
    runif(20)
  )   # "external" comment

led to:

    # internal comment
    fun1(a, b, c, d, e, f)
    # "external" comment
    fun1(a)

Not clear whether this is a parse_with_comments issue or a translation issue.