Add test

Author: lthls

ocaml/testsuite/tests/letrec-compilation/store_in_local.ml

@@ -0,0 +1,7 @@
+(* TEST *)
+
+(* If stack allocation is enabled, the record will be allocated locally.
+   This is allowed by the type-checker, but the dissect_letrec code
+   choked on it. *)
+type t = { a : int }
+let rec x = let _ = { a = x } in 3