numfmt: apply prefix after scaling for --to-unit (#11684)

* numfmt: apply suffix after scaling

* test_numfmt: remove ignore from prefix selection test

src/uu/numfmt/src/format.rs

@@ -487,8 +487,8 @@ fn transform_to(
     precision: usize,
     unit_separator: &str,
 ) -> Result<String> {
-    let (i2, s) = consider_suffix(s, opts.to, round_method, precision)?;
-    let i2 = i2 / (opts.to_unit as f64);
+    let i2 = s / (opts.to_unit as f64);
+    let (i2, s) = consider_suffix(i2, opts.to, round_method, precision)?;
     Ok(match s {
         None => {
             format!(

tests/by-util/test_numfmt.rs

@@ -1436,12 +1436,8 @@ fn test_zero_pad_sign_order_issue_11664() {
         .stdout_is("-00000009869647.00\n");
 }
 
-// https://github.com/uutils/coreutils/issues/11666
-// `--to-unit=N` selects the output prefix based on the unscaled value
-// instead of `value / N`.
 #[test]
-#[ignore = "GNU compat: see uutils/coreutils#11666"]
-fn test_to_unit_prefix_selection_issue_11666() {
+fn test_to_unit_prefix_selection() {
     new_ucmd!()
         .args(&["--to=iec-i", "--to-unit=885", "100000"])
         .succeeds()