check-pass test for a MRE of #135020

Signed-off-by: FedericoBruzzone <federico.bruzzone.i@gmail.com>

Author: FedericoBruzzone

tests/crashes/135020.rs

@@ -0,0 +1,7 @@
+//@ check-pass
+
+fn problem_thingy(items: &mut impl Iterator<Item = str>) {
+    items.peekable();
+}
+
+fn main() {}