chore: add (failing) grind test for a regression from #9814

tests/lean/grind/match.lean

@@ -0,0 +1,13 @@
+
+abbrev F : Fin 3 → Nat
+| 0 => 0
+| 1 => 1
+| 2 => 2
+
+abbrev Pairwise (r : α → α → Prop) :=
+  ∀ ⦃i j⦄, i ≠ j → r i j
+
+abbrev onFun (f : β → β → φ) (g : α → β) : α → α → φ := fun x y => f (g x) (g y)
+
+example : Pairwise (onFun (fun a b => a + b < 10) fun x ↦ F x) := by
+  grind