Order list-min-size tests in descending order

Some of the head-constructor tests we generate can be supersets of other tests.
Edges must be ordered so that more general tests always happen after their
specialized variants.

For example, patterns

  [1, ..] -> ...
  [2, 1, ..] -> ...

may generate the edges

  ListLen(>=1) -> <rest>
  ListLen(>=2) -> <rest>

but evaluated in exactly this order, the second edge is never reachable.
The necessary ordering is

  ListLen(>=2) -> <rest>
  ListLen(>=1) -> <rest>

Closes #4732

crates/compiler/test_mono/src/tests.rs

@@ -2220,3 +2220,17 @@ fn lambda_set_with_imported_toplevels_issue_4733() {
         "###
     )
 }
+
+#[mono_test]
+fn order_list_size_tests_issue_4732() {
+    indoc!(
+        r###"
+        when [] is 
+            [1, ..]          -> "B1"
+            [2, 1, ..]       -> "B2"
+            [3, 2, 1, ..]    -> "B3"
+            [4, 3, 2, 1, ..] -> "B4"
+            _                -> "Catchall"
+        "###
+    )
+}