qemublocktest: Add 'empty' case for blockcopy bitmap handling test

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

tests/qemublocktest.c

@@ -1408,6 +1408,9 @@ mymain(void)
             ret = -1; \
     } while (0)
 
+    TEST_BITMAP_BLOCKCOPY("empty-shallow", true, "empty");
+    TEST_BITMAP_BLOCKCOPY("empty-deep", false, "empty");
+
     TEST_BITMAP_BLOCKCOPY("basic-shallow", true, "basic");
     TEST_BITMAP_BLOCKCOPY("basic-deep", false, "basic");