Added a lossless test

It does encodings with min and max q set at 0, and check to make sure
output PSNR at MAX_PSNR (100).

Change-Id: Ia2418353cccf6e487204ea4ff874a7e71e55cb3e

test/test.mk

diff --git a/test/test.mk b/test/test.mk
index 52a54fb..c2a3aec 100644
--- a/test/test.mk
+++ b/test/test.mk
@@ -26,6 +26,7 @@
 LIBVPX_TEST_SRCS-$(CONFIG_VP9_ENCODER) += borders_test.cc
 LIBVPX_TEST_SRCS-$(CONFIG_VP8_ENCODER) += resize_test.cc
 LIBVPX_TEST_SRCS-$(CONFIG_VP9_ENCODER) += cpu_speed_test.cc
+LIBVPX_TEST_SRCS-$(CONFIG_VP9_ENCODER) += vp9_lossless_test.cc
 
 LIBVPX_TEST_SRCS-$(CONFIG_DECODERS)    += ../md5_utils.h ../md5_utils.c
 LIBVPX_TEST_SRCS-yes                   += decode_test_driver.cc