Fix infix:<x> accidentally silencing failures

An earlier fix[^1] to interpret type objects as 0 iterations had an unintended
effect that Failures from the coercion of the RHS argument to Int would also be
silently treaded as 0.

Add a separate multi for type objects to handle that case, leaving
coercion Failures able to freely explode.

Fixes RT#129899: https://rt.perl.org/Ticket/Display.html?id=129899
[1] 2311372

src/core/Stringy.pm

@@ -23,7 +23,8 @@ multi sub infix:<x>($s, Num:D $n) {
       ?? Failure.new(X::NYI.new(:feature('Cat object')))
       !! $s.Stringy x $n.Int;
 }
-multi sub infix:<x>($s, $n)        { $s.Stringy x ($n.Int // 0) }
+multi sub infix:<x>($s, Any:D $n) { $s.Stringy x $n.Int }
+multi sub infix:<x>($s, Any:U $n) { $s.Stringy x 0      }
 
 proto sub infix:<leg>(Mu $?, Mu $?) is pure { * }
 multi sub infix:<leg>(\a, \b)      { a.Stringy cmp b.Stringy }