improve mallinfo test

test/mallinfo.c

@@ -4,13 +4,9 @@
 
 #include "test_util.h"
 
-OPTNONE int main(void) {
-    malloc(1024 * 1024 * 1024);
-    malloc(16);
-    malloc(32);
-    malloc(64);
-
+static void print_mallinfo(void) {
     struct mallinfo info = mallinfo();
+    printf("mallinfo:\n");
     printf("arena: %zu\n", info.arena);
     printf("ordblks: %zu\n", info.ordblks);
     printf("smblks: %zu\n", info.smblks);
@@ -22,3 +18,22 @@ OPTNONE int main(void) {
     printf("fordblks: %zu\n", info.fordblks);
     printf("keepcost: %zu\n", info.keepcost);
 }
+
+OPTNONE int main(void) {
+    void *a[4];
+
+    a[0] = malloc(1024 * 1024 * 1024);
+    a[1] = malloc(16);
+    a[2] = malloc(32);
+    a[3] = malloc(64);
+
+    print_mallinfo();
+
+    free(a[0]);
+    free(a[1]);
+    free(a[2]);
+    free(a[3]);
+
+    printf("\n");
+    print_mallinfo();
+}