global `const` variables to primitives do not need to be FMCL'd

[samualtnorman]

const foo = "bar"

export default () => foo

becomes (with --no-minify)

function() {
  let _01ok1tkk9jd_G_ = #G
  if (!#FMCL) {
    _01ok1tkk9jd_G_.foo = "bar"
  }
  return _01ok1tkk9jd_G_.foo
}

which is a bit unnecessary

ideally it should just become

function() {
  let foo = "bar"
  return foo
}