lib544.c: use duphandle for test 545

To verify that curl_easy_duphandle() works fine on a handle that has
gotten data stored with *_COPYPOSTFIELDS.

tests/libtest/lib544.c

@@ -68,6 +68,16 @@ int test(char *URL)
   /* Update the original data to detect non-copy. */
   strcpy(teststring, "FAIL");
 
+#ifdef LIB545
+  {
+    CURL *handle2;
+    handle2 = curl_easy_duphandle(curl);
+    curl_easy_cleanup(curl);
+
+    curl = handle2;
+  }
+#endif
+
   /* Now, this is a POST request with binary 0 embedded in POST data. */
   res = curl_easy_perform(curl);