test/930: free-in-a-loop row pins no per-iteration stack damage (#27 review)

test/wcc/930_free_noop_run.c

@@ -15,6 +15,8 @@
  * no-op's documented leak semantics — the pointee stays valid), free
  * of a struct field, free of a CALL operand twice (the side effect
  * must run per call — a global counter observes both evaluations),
+ * free in a 1M-iteration loop (the no-op must not accumulate stack
+ * damage — a leaked push per free would segfault),
  * and the Hare-port shape alloc-then-free round-trip (import rt;
  * *i64 — i64 sidesteps the pre-existing unrelated cs≠ww alloc(value)
  * size divergence on narrow pointee types, filed separately). The
@@ -93,6 +95,26 @@ static const struct row rows[] = {
 	  "    return 0;\n"
 	  "};\n",
 	  0 },
+	/* free() in a hot loop: the no-op must not accumulate stack
+	 * damage — a leaked 8B push per free would blow the 8MiB stack
+	 * long before 1M iterations (segfault, not a wrong exit code). */
+	{ "free_loop_no_stack_damage",
+	  "let g: i32 = 0;\n"
+	  "fn bump(p: *i32) *i32 = {\n"
+	  "    g = g + 1;\n"
+	  "    return p;\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "    let x: i32 = 1;\n"
+	  "    let i: i32 = 0;\n"
+	  "    for (i < 1000000) {\n"
+	  "        free(bump(&x));\n"
+	  "        i += 1;\n"
+	  "    };\n"
+	  "    if (g != 1000000) { return 5; };\n"
+	  "    return 0;\n"
+	  "};\n",
+	  0 },
 	/* The verbatim Hare-port shape: alloc then free, deref after.
 	 * Pre-#27 this was THE w6l undefined-reference repro. */
 	{ "free_alloc_roundtrip",