tests: Fix fps test by increasing ring buffer

test/test_4_formats.cpp

@@ -153,6 +153,7 @@ TEST(FormatTests, h265_large_fps)
             sender->configure_ctx(RCC_FPS_DENOMINATOR, 1);
 
             receiver->configure_ctx(RCC_UDP_RCV_BUF_SIZE, 40 * 1000 * 1000);
+            receiver->configure_ctx(RCC_RING_BUFFER_SIZE, 40 * 1000 * 1000);
         }
     }