Enable missing dual lpf test

Found with -Wunused-function
Change-Id: I4aee260016ae522e3fbbd72977ff09a8ebe5f3cf

test/lpf_8_test.cc

diff --git a/test/lpf_8_test.cc b/test/lpf_8_test.cc
index 966e109..0bf6b0c 100644
--- a/test/lpf_8_test.cc
+++ b/test/lpf_8_test.cc
@@ -590,7 +590,9 @@
         make_tuple(&vpx_lpf_horizontal_16_sse2, &vpx_lpf_horizontal_16_c, 8, 1),
         make_tuple(&vpx_lpf_horizontal_16_sse2, &vpx_lpf_horizontal_16_c, 8, 2),
         make_tuple(&vpx_lpf_vertical_8_sse2, &vpx_lpf_vertical_8_c, 8, 1),
-        make_tuple(&wrapper_vertical_16_sse2, &wrapper_vertical_16_c, 8, 1)));
+        make_tuple(&wrapper_vertical_16_sse2, &wrapper_vertical_16_c, 8, 1),
+        make_tuple(&wrapper_vertical_16_dual_sse2,
+                   &wrapper_vertical_16_dual_c, 8, 1)));
 #endif  // CONFIG_VP9_HIGHBITDEPTH
 #endif