Move memory corruption tests up a directory

test/double_free_small_delayed.c

@@ -0,0 +1,18 @@
+#include <stdlib.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    void *p = malloc(16);
+    if (!p) {
+        return 1;
+    }
+    void *q = malloc(16);
+    if (!q) {
+        return 1;
+    }
+    free(p);
+    free(q);
+    free(p);
+    return 0;
+}