perf: allow boxed scalars passed to scalar params to be borrowed (#9360)

src/Lean/Compiler/IR/Borrow.lean

@@ -196,7 +196,7 @@ def ownArgsUsingParams (xs : Array Arg) (ps : Array Param) : M Unit :=
   xs.size.forM fun i _ => do
     let x := xs[i]
     let p := ps[i]!
-    unless p.borrow do ownArg x
+    unless p.borrow || p.ty.isScalar do ownArg x
 
 /-- For each xs[i], if xs[i] is owned, then mark ps[i] as owned.
    We use this action to preserve tail calls. That is, if we have